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  • Highly available iSCSI target

    - by sysetr
    I'm in the process of setting up iSCSI target on DRBD following the steps detailed here. I would appreciate if someone can answer and explain the following queries: Is there a way to set up just 1 resource for iscsi config and storage? Why does iscsi.config have to have a separate resource (in drbd.conf). Is it possible to put iscsi.config and iscsi.target in one disk? If not possible, what would be a good ratio (space wise) for iscsi.config and iscsi.target? Assuming I need to set up a 1TB iscsi.storage, how much space should I allocate for iscsi.config?

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  • Bar Table Modded Into Standing Desk

    - by Jason Fitzpatrick
    This polished looking standing desk combines a stand alone bar-height counter with extra storage, cable management, and monitor riser. The end result looks like a $$$$ standing desk at a fraction of the price. Courtesy of IKEA hacker Marc Marton, the build combines the Billsta Bar Table, the Ekby Alex Shelf, and Besta legs to raise the shelf up off the desk and create a keyboard storage area. For more information about the build hit up the link below. Billsta Bar Table into Standing Work Station [IKEAHacker] 8 Deadly Commands You Should Never Run on Linux 14 Special Google Searches That Show Instant Answers How To Create a Customized Windows 7 Installation Disc With Integrated Updates

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  • Hyper-V File Server Clustering - at my wit’s end

    - by René Kåbis
    I am at my wit’s end with File Server clustering under Hyper-V. I am hoping that someone might be able to help me figure out this Gordian Knot of a technology that seems to have dead ends (like forcing cluster VMs to use iSCSI drives where normally-attached VHDX drives could suffice) where logic and reason would normally provide a logical solution. My hardware: I will be running three servers (in the end), but right now everything is taking place on one server. One of the secondary servers will exist purely as a witness/quorum, and another slightly more powerful one will be acting as an emergency backup (with additional storage, just not redundant) to hold the secondary AD VM and the other halves of a set of clustered VMs: the SQL VM and the file system VM. Please note, these each are the depreciated nodes of a cluster, the main nodes will be on the most powerful first machine. My heavy lifter is a machine that also contains all of the truly redundant storage on the network. If this gives anyone the heebie-geebies, too bad. It has a 6TB (usable) RAID-10 array, and will (in the end) hold the primary nodes of both aforementioned clusters, but is right now holding all VMs. This is, right now: DC01, DC02, SQL01, SQL02, FS01 & FS02. Eventually, I will be adding additional VMs to handle Exchange, Sharepoint and Lync, but only to this main server (the secondary server won't be able to handle more than three or four VMs, so why burden it? The AD, SQL & FS VMs are the most critical for the business). If anyone is now saying, “wait, what about a SAN or a NAS for the file servers?”, well too bad. What exists on the main machine is what I have to deal with. I followed these instructions, but I seem to be unable to get things to work. In order to make the file server truly redundant, I cannot trust any one machine to hold the only data store on the network. Therefore, I have created a set of iSCSI drives on the VM-host of the main machine, and attached one to each file server VM. The end result is that I want my FS01 to sit on the heavy lifter, along with its iSCSI “drive”, and FS02 will sit on the secondary machine with its own iSCSI “drive” there as well. That is, neither iSCSI drive will end up sitting on the same machine as the other. As such, the clustered FS will utterly duplicate the contents of the iSCSI drives between each other, so that if one physical machine (or the FS VM) goes toes-up, the other has got a full copy of the data on its own iSCSI drive. My problem occurs when I try to apply the file server role within the failover cluster manager. Actually, it is even before that -- it occurs when adding the disks. Since I have added each disk preferentially to a specific VM (by limiting the initiator by DNS hostname, and by adding two-way CHAP authentication), this forces each VM to be in control of its own iSCSI disk. However, when I try to add the disks to the Disks section of Storage within Failover Cluster Manager, the entire process fails for a random disk of the pair. That is, one will get online, but the other will remain offline because it does not have the correct “owner node”. I mean, really -- WTF? Of course it doesn’t have the right owner node, both drives are showing the same node name!! I cannot seem to have one drive show up with one node name as owner, and the other drive show up with the other node name as owner. And because both drives are not “online”, I cannot create a pool to apply to a cluster role. Talk about getting stuck between a rock and a hard place! I’ve got more to add, but my work is closing for the day and I have to wrap things up. I will try to add more tomorrow morning when I get in. My main objective is to have a file server VM on each machine, the storage on each machine, but a transparent failover in case one physical machine fails. Essentially, a failover FS that doesn’t care which machine fails -- the storage contents are replicated equally on each machine. Am I even heading in the right direction?

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  • Advanced TSQL Tuning: Why Internals Knowledge Matters

    - by Paul White
    There is much more to query tuning than reducing logical reads and adding covering nonclustered indexes.  Query tuning is not complete as soon as the query returns results quickly in the development or test environments.  In production, your query will compete for memory, CPU, locks, I/O and other resources on the server.  Today’s entry looks at some tuning considerations that are often overlooked, and shows how deep internals knowledge can help you write better TSQL. As always, we’ll need some example data.  In fact, we are going to use three tables today, each of which is structured like this: Each table has 50,000 rows made up of an INTEGER id column and a padding column containing 3,999 characters in every row.  The only difference between the three tables is in the type of the padding column: the first table uses CHAR(3999), the second uses VARCHAR(MAX), and the third uses the deprecated TEXT type.  A script to create a database with the three tables and load the sample data follows: USE master; GO IF DB_ID('SortTest') IS NOT NULL DROP DATABASE SortTest; GO CREATE DATABASE SortTest COLLATE LATIN1_GENERAL_BIN; GO ALTER DATABASE SortTest MODIFY FILE ( NAME = 'SortTest', SIZE = 3GB, MAXSIZE = 3GB ); GO ALTER DATABASE SortTest MODIFY FILE ( NAME = 'SortTest_log', SIZE = 256MB, MAXSIZE = 1GB, FILEGROWTH = 128MB ); GO ALTER DATABASE SortTest SET ALLOW_SNAPSHOT_ISOLATION OFF ; ALTER DATABASE SortTest SET AUTO_CLOSE OFF ; ALTER DATABASE SortTest SET AUTO_CREATE_STATISTICS ON ; ALTER DATABASE SortTest SET AUTO_SHRINK OFF ; ALTER DATABASE SortTest SET AUTO_UPDATE_STATISTICS ON ; ALTER DATABASE SortTest SET AUTO_UPDATE_STATISTICS_ASYNC ON ; ALTER DATABASE SortTest SET PARAMETERIZATION SIMPLE ; ALTER DATABASE SortTest SET READ_COMMITTED_SNAPSHOT OFF ; ALTER DATABASE SortTest SET MULTI_USER ; ALTER DATABASE SortTest SET RECOVERY SIMPLE ; USE SortTest; GO CREATE TABLE dbo.TestCHAR ( id INTEGER IDENTITY (1,1) NOT NULL, padding CHAR(3999) NOT NULL,   CONSTRAINT [PK dbo.TestCHAR (id)] PRIMARY KEY CLUSTERED (id), ) ; CREATE TABLE dbo.TestMAX ( id INTEGER IDENTITY (1,1) NOT NULL, padding VARCHAR(MAX) NOT NULL,   CONSTRAINT [PK dbo.TestMAX (id)] PRIMARY KEY CLUSTERED (id), ) ; CREATE TABLE dbo.TestTEXT ( id INTEGER IDENTITY (1,1) NOT NULL, padding TEXT NOT NULL,   CONSTRAINT [PK dbo.TestTEXT (id)] PRIMARY KEY CLUSTERED (id), ) ; -- ============= -- Load TestCHAR (about 3s) -- ============= INSERT INTO dbo.TestCHAR WITH (TABLOCKX) ( padding ) SELECT padding = REPLICATE(CHAR(65 + (Data.n % 26)), 3999) FROM ( SELECT TOP (50000) n = ROW_NUMBER() OVER (ORDER BY (SELECT 0)) - 1 FROM master.sys.columns C1, master.sys.columns C2, master.sys.columns C3 ORDER BY n ASC ) AS Data ORDER BY Data.n ASC ; -- ============ -- Load TestMAX (about 3s) -- ============ INSERT INTO dbo.TestMAX WITH (TABLOCKX) ( padding ) SELECT CONVERT(VARCHAR(MAX), padding) FROM dbo.TestCHAR ORDER BY id ; -- ============= -- Load TestTEXT (about 5s) -- ============= INSERT INTO dbo.TestTEXT WITH (TABLOCKX) ( padding ) SELECT CONVERT(TEXT, padding) FROM dbo.TestCHAR ORDER BY id ; -- ========== -- Space used -- ========== -- EXECUTE sys.sp_spaceused @objname = 'dbo.TestCHAR'; EXECUTE sys.sp_spaceused @objname = 'dbo.TestMAX'; EXECUTE sys.sp_spaceused @objname = 'dbo.TestTEXT'; ; CHECKPOINT ; That takes around 15 seconds to run, and shows the space allocated to each table in its output: To illustrate the points I want to make today, the example task we are going to set ourselves is to return a random set of 150 rows from each table.  The basic shape of the test query is the same for each of the three test tables: SELECT TOP (150) T.id, T.padding FROM dbo.Test AS T ORDER BY NEWID() OPTION (MAXDOP 1) ; Test 1 – CHAR(3999) Running the template query shown above using the TestCHAR table as the target, we find that the query takes around 5 seconds to return its results.  This seems slow, considering that the table only has 50,000 rows.  Working on the assumption that generating a GUID for each row is a CPU-intensive operation, we might try enabling parallelism to see if that speeds up the response time.  Running the query again (but without the MAXDOP 1 hint) on a machine with eight logical processors, the query now takes 10 seconds to execute – twice as long as when run serially. Rather than attempting further guesses at the cause of the slowness, let’s go back to serial execution and add some monitoring.  The script below monitors STATISTICS IO output and the amount of tempdb used by the test query.  We will also run a Profiler trace to capture any warnings generated during query execution. DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) TC.id, TC.padding FROM dbo.TestCHAR AS TC ORDER BY NEWID() OPTION (MAXDOP 1) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; Let’s take a closer look at the statistics and query plan generated from this: Following the flow of the data from right to left, we see the expected 50,000 rows emerging from the Clustered Index Scan, with a total estimated size of around 191MB.  The Compute Scalar adds a column containing a random GUID (generated from the NEWID() function call) for each row.  With this extra column in place, the size of the data arriving at the Sort operator is estimated to be 192MB. Sort is a blocking operator – it has to examine all of the rows on its input before it can produce its first row of output (the last row received might sort first).  This characteristic means that Sort requires a memory grant – memory allocated for the query’s use by SQL Server just before execution starts.  In this case, the Sort is the only memory-consuming operator in the plan, so it has access to the full 243MB (248,696KB) of memory reserved by SQL Server for this query execution. Notice that the memory grant is significantly larger than the expected size of the data to be sorted.  SQL Server uses a number of techniques to speed up sorting, some of which sacrifice size for comparison speed.  Sorts typically require a very large number of comparisons, so this is usually a very effective optimization.  One of the drawbacks is that it is not possible to exactly predict the sort space needed, as it depends on the data itself.  SQL Server takes an educated guess based on data types, sizes, and the number of rows expected, but the algorithm is not perfect. In spite of the large memory grant, the Profiler trace shows a Sort Warning event (indicating that the sort ran out of memory), and the tempdb usage monitor shows that 195MB of tempdb space was used – all of that for system use.  The 195MB represents physical write activity on tempdb, because SQL Server strictly enforces memory grants – a query cannot ‘cheat’ and effectively gain extra memory by spilling to tempdb pages that reside in memory.  Anyway, the key point here is that it takes a while to write 195MB to disk, and this is the main reason that the query takes 5 seconds overall. If you are wondering why using parallelism made the problem worse, consider that eight threads of execution result in eight concurrent partial sorts, each receiving one eighth of the memory grant.  The eight sorts all spilled to tempdb, resulting in inefficiencies as the spilled sorts competed for disk resources.  More importantly, there are specific problems at the point where the eight partial results are combined, but I’ll cover that in a future post. CHAR(3999) Performance Summary: 5 seconds elapsed time 243MB memory grant 195MB tempdb usage 192MB estimated sort set 25,043 logical reads Sort Warning Test 2 – VARCHAR(MAX) We’ll now run exactly the same test (with the additional monitoring) on the table using a VARCHAR(MAX) padding column: DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) TM.id, TM.padding FROM dbo.TestMAX AS TM ORDER BY NEWID() OPTION (MAXDOP 1) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; This time the query takes around 8 seconds to complete (3 seconds longer than Test 1).  Notice that the estimated row and data sizes are very slightly larger, and the overall memory grant has also increased very slightly to 245MB.  The most marked difference is in the amount of tempdb space used – this query wrote almost 391MB of sort run data to the physical tempdb file.  Don’t draw any general conclusions about VARCHAR(MAX) versus CHAR from this – I chose the length of the data specifically to expose this edge case.  In most cases, VARCHAR(MAX) performs very similarly to CHAR – I just wanted to make test 2 a bit more exciting. MAX Performance Summary: 8 seconds elapsed time 245MB memory grant 391MB tempdb usage 193MB estimated sort set 25,043 logical reads Sort warning Test 3 – TEXT The same test again, but using the deprecated TEXT data type for the padding column: DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) TT.id, TT.padding FROM dbo.TestTEXT AS TT ORDER BY NEWID() OPTION (MAXDOP 1, RECOMPILE) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; This time the query runs in 500ms.  If you look at the metrics we have been checking so far, it’s not hard to understand why: TEXT Performance Summary: 0.5 seconds elapsed time 9MB memory grant 5MB tempdb usage 5MB estimated sort set 207 logical reads 596 LOB logical reads Sort warning SQL Server’s memory grant algorithm still underestimates the memory needed to perform the sorting operation, but the size of the data to sort is so much smaller (5MB versus 193MB previously) that the spilled sort doesn’t matter very much.  Why is the data size so much smaller?  The query still produces the correct results – including the large amount of data held in the padding column – so what magic is being performed here? TEXT versus MAX Storage The answer lies in how columns of the TEXT data type are stored.  By default, TEXT data is stored off-row in separate LOB pages – which explains why this is the first query we have seen that records LOB logical reads in its STATISTICS IO output.  You may recall from my last post that LOB data leaves an in-row pointer to the separate storage structure holding the LOB data. SQL Server can see that the full LOB value is not required by the query plan until results are returned, so instead of passing the full LOB value down the plan from the Clustered Index Scan, it passes the small in-row structure instead.  SQL Server estimates that each row coming from the scan will be 79 bytes long – 11 bytes for row overhead, 4 bytes for the integer id column, and 64 bytes for the LOB pointer (in fact the pointer is rather smaller – usually 16 bytes – but the details of that don’t really matter right now). OK, so this query is much more efficient because it is sorting a very much smaller data set – SQL Server delays retrieving the LOB data itself until after the Sort starts producing its 150 rows.  The question that normally arises at this point is: Why doesn’t SQL Server use the same trick when the padding column is defined as VARCHAR(MAX)? The answer is connected with the fact that if the actual size of the VARCHAR(MAX) data is 8000 bytes or less, it is usually stored in-row in exactly the same way as for a VARCHAR(8000) column – MAX data only moves off-row into LOB storage when it exceeds 8000 bytes.  The default behaviour of the TEXT type is to be stored off-row by default, unless the ‘text in row’ table option is set suitably and there is room on the page.  There is an analogous (but opposite) setting to control the storage of MAX data – the ‘large value types out of row’ table option.  By enabling this option for a table, MAX data will be stored off-row (in a LOB structure) instead of in-row.  SQL Server Books Online has good coverage of both options in the topic In Row Data. The MAXOOR Table The essential difference, then, is that MAX defaults to in-row storage, and TEXT defaults to off-row (LOB) storage.  You might be thinking that we could get the same benefits seen for the TEXT data type by storing the VARCHAR(MAX) values off row – so let’s look at that option now.  This script creates a fourth table, with the VARCHAR(MAX) data stored off-row in LOB pages: CREATE TABLE dbo.TestMAXOOR ( id INTEGER IDENTITY (1,1) NOT NULL, padding VARCHAR(MAX) NOT NULL,   CONSTRAINT [PK dbo.TestMAXOOR (id)] PRIMARY KEY CLUSTERED (id), ) ; EXECUTE sys.sp_tableoption @TableNamePattern = N'dbo.TestMAXOOR', @OptionName = 'large value types out of row', @OptionValue = 'true' ; SELECT large_value_types_out_of_row FROM sys.tables WHERE [schema_id] = SCHEMA_ID(N'dbo') AND name = N'TestMAXOOR' ; INSERT INTO dbo.TestMAXOOR WITH (TABLOCKX) ( padding ) SELECT SPACE(0) FROM dbo.TestCHAR ORDER BY id ; UPDATE TM WITH (TABLOCK) SET padding.WRITE (TC.padding, NULL, NULL) FROM dbo.TestMAXOOR AS TM JOIN dbo.TestCHAR AS TC ON TC.id = TM.id ; EXECUTE sys.sp_spaceused @objname = 'dbo.TestMAXOOR' ; CHECKPOINT ; Test 4 – MAXOOR We can now re-run our test on the MAXOOR (MAX out of row) table: DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) MO.id, MO.padding FROM dbo.TestMAXOOR AS MO ORDER BY NEWID() OPTION (MAXDOP 1, RECOMPILE) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; TEXT Performance Summary: 0.3 seconds elapsed time 245MB memory grant 0MB tempdb usage 193MB estimated sort set 207 logical reads 446 LOB logical reads No sort warning The query runs very quickly – slightly faster than Test 3, and without spilling the sort to tempdb (there is no sort warning in the trace, and the monitoring query shows zero tempdb usage by this query).  SQL Server is passing the in-row pointer structure down the plan and only looking up the LOB value on the output side of the sort. The Hidden Problem There is still a huge problem with this query though – it requires a 245MB memory grant.  No wonder the sort doesn’t spill to tempdb now – 245MB is about 20 times more memory than this query actually requires to sort 50,000 records containing LOB data pointers.  Notice that the estimated row and data sizes in the plan are the same as in test 2 (where the MAX data was stored in-row). The optimizer assumes that MAX data is stored in-row, regardless of the sp_tableoption setting ‘large value types out of row’.  Why?  Because this option is dynamic – changing it does not immediately force all MAX data in the table in-row or off-row, only when data is added or actually changed.  SQL Server does not keep statistics to show how much MAX or TEXT data is currently in-row, and how much is stored in LOB pages.  This is an annoying limitation, and one which I hope will be addressed in a future version of the product. So why should we worry about this?  Excessive memory grants reduce concurrency and may result in queries waiting on the RESOURCE_SEMAPHORE wait type while they wait for memory they do not need.  245MB is an awful lot of memory, especially on 32-bit versions where memory grants cannot use AWE-mapped memory.  Even on a 64-bit server with plenty of memory, do you really want a single query to consume 0.25GB of memory unnecessarily?  That’s 32,000 8KB pages that might be put to much better use. The Solution The answer is not to use the TEXT data type for the padding column.  That solution happens to have better performance characteristics for this specific query, but it still results in a spilled sort, and it is hard to recommend the use of a data type which is scheduled for removal.  I hope it is clear to you that the fundamental problem here is that SQL Server sorts the whole set arriving at a Sort operator.  Clearly, it is not efficient to sort the whole table in memory just to return 150 rows in a random order. The TEXT example was more efficient because it dramatically reduced the size of the set that needed to be sorted.  We can do the same thing by selecting 150 unique keys from the table at random (sorting by NEWID() for example) and only then retrieving the large padding column values for just the 150 rows we need.  The following script implements that idea for all four tables: SET STATISTICS IO ON ; WITH TestTable AS ( SELECT * FROM dbo.TestCHAR ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id = ANY (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; WITH TestTable AS ( SELECT * FROM dbo.TestMAX ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id IN (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; WITH TestTable AS ( SELECT * FROM dbo.TestTEXT ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id IN (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; WITH TestTable AS ( SELECT * FROM dbo.TestMAXOOR ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id IN (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; SET STATISTICS IO OFF ; All four queries now return results in much less than a second, with memory grants between 6 and 12MB, and without spilling to tempdb.  The small remaining inefficiency is in reading the id column values from the clustered primary key index.  As a clustered index, it contains all the in-row data at its leaf.  The CHAR and VARCHAR(MAX) tables store the padding column in-row, so id values are separated by a 3999-character column, plus row overhead.  The TEXT and MAXOOR tables store the padding values off-row, so id values in the clustered index leaf are separated by the much-smaller off-row pointer structure.  This difference is reflected in the number of logical page reads performed by the four queries: Table 'TestCHAR' logical reads 25511 lob logical reads 000 Table 'TestMAX'. logical reads 25511 lob logical reads 000 Table 'TestTEXT' logical reads 00412 lob logical reads 597 Table 'TestMAXOOR' logical reads 00413 lob logical reads 446 We can increase the density of the id values by creating a separate nonclustered index on the id column only.  This is the same key as the clustered index, of course, but the nonclustered index will not include the rest of the in-row column data. CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestCHAR (id); CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestMAX (id); CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestTEXT (id); CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestMAXOOR (id); The four queries can now use the very dense nonclustered index to quickly scan the id values, sort them by NEWID(), select the 150 ids we want, and then look up the padding data.  The logical reads with the new indexes in place are: Table 'TestCHAR' logical reads 835 lob logical reads 0 Table 'TestMAX' logical reads 835 lob logical reads 0 Table 'TestTEXT' logical reads 686 lob logical reads 597 Table 'TestMAXOOR' logical reads 686 lob logical reads 448 With the new index, all four queries use the same query plan (click to enlarge): Performance Summary: 0.3 seconds elapsed time 6MB memory grant 0MB tempdb usage 1MB sort set 835 logical reads (CHAR, MAX) 686 logical reads (TEXT, MAXOOR) 597 LOB logical reads (TEXT) 448 LOB logical reads (MAXOOR) No sort warning I’ll leave it as an exercise for the reader to work out why trying to eliminate the Key Lookup by adding the padding column to the new nonclustered indexes would be a daft idea Conclusion This post is not about tuning queries that access columns containing big strings.  It isn’t about the internal differences between TEXT and MAX data types either.  It isn’t even about the cool use of UPDATE .WRITE used in the MAXOOR table load.  No, this post is about something else: Many developers might not have tuned our starting example query at all – 5 seconds isn’t that bad, and the original query plan looks reasonable at first glance.  Perhaps the NEWID() function would have been blamed for ‘just being slow’ – who knows.  5 seconds isn’t awful – unless your users expect sub-second responses – but using 250MB of memory and writing 200MB to tempdb certainly is!  If ten sessions ran that query at the same time in production that’s 2.5GB of memory usage and 2GB hitting tempdb.  Of course, not all queries can be rewritten to avoid large memory grants and sort spills using the key-lookup technique in this post, but that’s not the point either. The point of this post is that a basic understanding of execution plans is not enough.  Tuning for logical reads and adding covering indexes is not enough.  If you want to produce high-quality, scalable TSQL that won’t get you paged as soon as it hits production, you need a deep understanding of execution plans, and as much accurate, deep knowledge about SQL Server as you can lay your hands on.  The advanced database developer has a wide range of tools to use in writing queries that perform well in a range of circumstances. By the way, the examples in this post were written for SQL Server 2008.  They will run on 2005 and demonstrate the same principles, but you won’t get the same figures I did because 2005 had a rather nasty bug in the Top N Sort operator.  Fair warning: if you do decide to run the scripts on a 2005 instance (particularly the parallel query) do it before you head out for lunch… This post is dedicated to the people of Christchurch, New Zealand. © 2011 Paul White email: @[email protected] twitter: @SQL_Kiwi

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  • Exadata support for ACFS (and thus, 10gR2) now available!

    - by Robert Freeman
    Really? Exadata, ACFS and 10gR2? If you work with Exadata you are probably aware that ACFS has not been supported - until now! ACFS is now supported on Exadata if you are running Grid Infrastructure version 12.1.0.2 or later. This new support is described in MOS note 1326938.1. Also Exadata support for ACFS is mentioned in MOS note 888828.1, which is the king of all Exadata notes on MOS. The upshot is that you can now run Oracle Database 10gR2 on Exadata using ACFS as the storage for the Oracle Database. Don’t Over React and just Throw Everything on ACFS!First, let’s be clear that ACFS is not an alternative for running your Exadata databases on ASM. If you are running any production or non-production performance sensitive Oracle databases on 11.2 or 12.1, then you should be running them on ASM disks that are associated with the storage cells. The use case for ACFS is generally limited to the following: Running any Oracle 10gR2 databases on Exadata. Running Oracle 11gR2 development or test databases that require rapid cloning, and that do not require the performance benefits of the Exadata storage cells. If you are running Oracle Database 12c and you need snapshot/clone kinds of capabilities, then you should be using Oracle MultiTennant and the features present in that option (remember though that MultiTennant is a licensed option). The Fine PrintThere are some requirements that you will need to meet If you are going to run ACFS on Exadata. These are: You have to use Oracle Linux You must use GI 12.1.0.2 or later If you wish to use HCC then you must apply the fix for bug 19136936 to your system. This bug, and it’s associated patch do not appear on MOS (as of the time that I wrote this) so you will need to open an SR and get support to provide the patch for you. The Best Use Case for ACFSEven though Oracle Database 10gR2 is at end of life, it remains in use in a large number of places. This has caused problems when choosing to implement Exadata as a consolidation platform, or when choosing it during a hardware refresh process. Now that ACFS is supported, Exadata has become even more flexible and affords customers greater flexibility when migrating to Exadata and Engineered Systems. While all of the features of Exadata might not be available to a 10.2.0.4 database, certainly just the improved processing capabilities of Exadata with its fast as heck infiniband network fabric, additional memory, reduced power requirements and a whole host of other features, justifies moving these databases to Exadata now. This will also make it easier to upgrade these databases when the time comes!

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  • SQL SERVER – SQL Server High Availability Options – Notes from the Field #032

    - by Pinal Dave
    [Notes from Pinal]: When it is about High Availability or Disaster Recovery, I often see people getting confused. There are so many options available that when the user has to select what is the most optimal solution for their organization they are often confused. Most of the people even know the salient features of various options, but when they have to figure out one single option to use they are often not sure which option to use. I like to give ask my dear friend time all these kinds of complicated questions. He has a skill to make a complex subject very simple and easy to understand. Linchpin People are database coaches and wellness experts for a data driven world. In this 26th episode of the Notes from the Fields series database expert Tim Radney (partner at Linchpin People) explains in a very simple words the best High Availability Option for your SQL Server.  Working with SQL Server a common challenge we are faced with is providing the maximum uptime possible.  To meet these demands we have to design a solution to provide High Availability (HA). Microsoft SQL Server depending on your edition provides you with several options.  This could be database mirroring, log shipping, failover clusters, availability groups or replication. Each possible solution comes with pro’s and con’s.  Not anyone one solution fits all scenarios so understanding which solution meets which need is important.  As with anything IT related, you need to fully understand your requirements before trying to solution the problem.  When it comes to building an HA solution, you need to understand the risk your organization needs to mitigate the most. I have found that most are concerned about hardware failure and OS failures. Other common concerns are data corruption or storage issues.  For data corruption or storage issues you can mitigate those concerns by having a second copy of the databases. That can be accomplished with database mirroring, log shipping, replication or availability groups with a secondary replica.  Failover clustering and virtualization with shared storage do not provide redundancy of the data. I recently created a chart outlining some pros and cons of each of the technologies that I posted on my blog. I like to use this chart to help illustrate how each technology provides a certain number of benefits.  Each of these solutions carries with it some level of cost and complexity.  As a database professional we should all be familiar with these technologies so we can make the best possible choice for our organization. If you want me to take a look at your server and its settings, or if your server is facing any issue we can Fix Your SQL Server. Note: Tim has also written an excellent book on SQL Backup and Recovery, a must have for everyone. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: Notes from the Field, PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Shrinking Database

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  • Adding additional users to Ubuntu server and configuring Samba

    - by Ben
    I have installed Ubuntu Server 12.10 and during the install created a user for myself ben, I now wish to add a second user bill. I have an external drive that I have mounted to /media/storage and created a shared folder called Share, the owner of the folder is ben:ben, how do I grant bill access to the folder? I don't want to put him in the group ben. Once setup, I need to configure Samba & NFS, here is my Samba configuration [Share] path = /media/storage/Share read only = no public = yes writeable = yes force user = ben How do I give both bill and ben access to the share via Samba? Thank you.

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  • Oracle Unbreakable Enterprise Kernel and Emulex HBA Eliminate Silent Data Corruption

    - by sergio.leunissen
    Yesterday, Emulex announced that it has added support for T10 Protection Information (T10-PI), formerly called T10-DIF, to a number of its HBAs. When used with Oracle's Unbreakable Enterprise Kernel, this will prevent silent data corruption and help ensure the integrity and regulatory compliance of user data as it is transferred from the application to the SAN From the press release: Traditionally, protecting the integrity of customers' data has been done with multiple discrete solutions, including Error Correcting Code (ECC) and Cyclic Redundancy Check (CRC), but there have been coverage gaps across the I/O path from the operating system to the storage. The implementation of the T10-PI standard via Emulex's BlockGuard feature, in conjunction with other industry player's implementations, ensures that data is validated as it moves through the data path, from the application, to the HBA, to storage, enabling seamless end-to-end integrity. Read the white paper and don't miss the live webcast on eliminating silent data corruption on December 16th!

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  • EM12c Release 4: Cloud Control to Major Tom...

    - by abulloch
    With the latest release of Enterprise Manager 12c, Release 4 (12.1.0.4) the EM development team has added new functionality to assist the EM Administrator to monitor the health of the EM infrastructure.   Taking feedback delivered from customers directly and through customer advisory boards some nice enhancements have been made to the “Manage Cloud Control” sections of the UI, commonly known in the EM community as “the MTM pages” (MTM stands for Monitor the Monitor).  This part of the EM Cloud Control UI is viewed by many as the mission control for EM Administrators. In this post we’ll highlight some of the new information that’s on display in these redesigned pages and explain how the information they present can help EM administrators identify potential bottlenecks or issues with the EM infrastructure. The first page we’ll take a look at is the newly designed Repository information page.  You can get to this from the main Setup menu, through Manage Cloud Control, then Repository.  Once this page loads you’ll see the new layout that includes 3 tabs containing more drill-down information. The Repository Tab The first tab, Repository, gives you a series of 6 panels or regions on screen that display key information that the EM Administrator needs to review from time to time to ensure that their infrastructure is in good health. Rather than go through every panel let’s call out a few and let you explore the others later yourself on your own EM site.  Firstly, we have the Repository Details panel. At a glance the EM Administrator can see the current version of the EM repository database and more critically, three important elements of information relating to availability and reliability :- Is the database in Archive Log mode ? Is the database using Flashback ? When was the last database backup taken ? In this test environment above the answers are not too worrying, however, Production environments should have at least Archivelog mode enabled, Flashback is a nice feature to enable prior to upgrades (for fast rollback) and all Production sites should have a backup.  In this case the backup information in the Control file indicates there’s been no recorded backups taken. The next region of interest to note on this page shows key information around the Repository configuration, specifically, the initialisation parameters (from the spfile). If you’re storing your EM Repository in a Cluster Database you can view the parameters on each individual instance using the Instance Name drop-down selector in the top right of the region. Additionally, you’ll note there is now a check performed on the active configuration to ensure that you’re using, at the very least, Oracle minimum recommended values.  Should the values in your EM Repository not meet these requirements it will be flagged in this table with a red X for non-compliance.  You can of-course change these values within EM by selecting the Database target and modifying the parameters in the spfile (and optionally, the run-time values if the parameter allows dynamic changes). The last region to call out on this page before moving on is the new look Repository Scheduler Job Status region. This region is an update of a similar region seen on previous releases of the MTM pages in Cloud Control but there’s some important new functionality that’s been added that customers have requested. First-up - Restarting Repository Jobs.  As you can see from the graphic, you can now optionally select a job (by selecting the row in the UI table element) and click on the Restart Job button to take care of any jobs which have stopped or stalled for any reason.  Previously this needed to be done at the command line using EMDIAG or through a PL/SQL package invocation.  You can now take care of this directly from within the UI. Next, you’ll see that a feature has been added to allow the EM administrator to customise the run-time for some of the background jobs that run in the Repository.  We heard from some customers that ensuring these jobs don’t clash with Production backups, etc is a key requirement.  This new functionality allows you to select the pencil icon to edit the schedule time for these more resource intensive background jobs and modify the schedule to avoid clashes like this. Moving onto the next tab, let’s select the Metrics tab. The Metrics Tab There’s some big changes here, this page contains new information regions that help the Administrator understand the direct impact the in-bound metric flows are having on the EM Repository.  Many customers have provided feedback that they are in the dark about the impact of adding new targets or large numbers of new hosts or new target types into EM and the impact this has on the Repository.  This page helps the EM Administrator get to grips with this.  Let’s take a quick look at two regions on this page. First-up there’s a bubble chart showing a comprehensive view of the top resource consumers of metric data, over the last 30 days, charted as the number of rows loaded against the number of collections for the metric.  The size of the bubble indicates a relative volume.  You can see from this example above that a quick glance shows that Host metrics are the largest inbound flow into the repository when measured by number of rows.  Closely following behind this though are a large number of collections for Oracle Weblogic Server and Application Deployment.  Taken together the Host Collections is around 0.7Mb of data.  The total information collection for Weblogic Server and Application Deployments is 0.38Mb and 0.37Mb respectively. If you want to get this information breakdown on the volume of data collected simply hover over the bubble in the chart and you’ll get a floating tooltip showing the information. Clicking on any bubble in the chart takes you one level deeper into a drill-down of the Metric collection. Doing this reveals the individual metric elements for these target types and again shows a representation of the relative cost - in terms of Number of Rows, Number of Collections and Storage cost of data for each Metric type. Looking at another panel on this page we can see a different view on this data. This view shows a view of the Top N metrics (the drop down allows you to select 10, 15 or 20) and sort them by volume of data.  In the case above we can see the largest metric collection (by volume) in this case (over the last 30 days) is the information about OS Registered Software on a Host target. Taken together, these two regions provide a powerful tool for the EM Administrator to understand the potential impact of any new targets that have been discovered and promoted into management by EM12c.  It’s a great tool for identifying the cause of a sudden increase in Repository storage consumption or Redo log and Archive log generation. Using the information on this page EM Administrators can take action to mitigate any load impact by deploying monitoring templates to the targets causing most load if appropriate.   The last tab we’ll look at on this page is the Schema tab. The Schema Tab Selecting this tab brings up a window onto the SYSMAN schema with a focus on Space usage in the EM Repository.  Understanding what tablespaces are growing, at what rate, is essential information for the EM Administrator to stay on top of managing space allocations for the EM Repository so that it works as efficiently as possible and performs well for the users.  Not least because ensuring storage is managed well ensures continued availability of EM for monitoring purposes. The first region to highlight here shows the trend of space usage for the tablespaces in the EM Repository over time.  You can see the upward trend here showing that storage in the EM Repository is being consumed on an upward trend over the last few days here. This is normal as this EM being used here is brand new with Agents being added daily to bring targets into monitoring.  If your Enterprise Manager configuration has reached a steady state over a period of time where the number of new inbound targets is relatively small, the metric collection settings are fairly uniform and standardised (using Templates and Template Collections) you’re likely to see a trend of space allocation that plateau’s. The table below the trend chart shows the Top 20 Tables/Indexes sorted descending by order of space consumed.  You can switch the trend view chart and corresponding detail table by choosing a different tablespace in the EM Repository using the drop-down picker on the top right of this region. The last region to highlight on this page is the region showing information about the Purge policies in effect in the EM Repository. This information is useful to illustrate to EM Administrators the default purge policies in effect for the different categories of information available in the EM Repository.  Of course, it’s also been a long requested feature to have the ability to modify these default retention periods.  You can also do this using this screen.  As there are interdependencies between some data elements you can’t modify retention policies on a feature by feature basis.  Instead, retention policies take categories of information and bundles them together in Groups.  Retention policies are modified at the Group Level.  Understanding the impact of this really deserves a blog post all on it’s own as modifying these can have a significant impact on both the EM Repository’s storage footprint and it’s performance.  For now, we’re just highlighting the features visibility on these new pages. As a user of EM12c we hope the new features you see here address some of the feedback that’s been given on these pages over the past few releases.  We’ll look out for any comments or feedback you have on these pages ! 

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  • Surface RT: To Be Or Not To Be (Part 1)

    - by smehaffie
    So the Surface RT has been out for 9 months and Microsoft just declared a $900 million dollar write-down. So how did this happen and what does it mean for Microsoft’s efforts to break into the tablet market? I have been thinking a lot about most of the information below since the Surface product line was released. If you are looking for a “Microsoft Is Dead” story, then don’t read any further. But if you want an honest look at what I think led Microsoft to this point and what I think can be done to make Surface RT devices better, then please continue reading. What Led Microsoft To The $900 Million Write-Down Surface Unveiling:Microsoft totally missed the boat when they unveiled the Surface product line on June 18th, 2012. Microsoft should’ve been ready to post the specifications of both devices that night. Microsoft should’ve had a site up and running right after the event so people could pre-order the devices. This would have given them a good idea what the interest was in each device.  They could also have used this data to make a better estimate for the number of units to to have available for the launch and beyond.  They also lost out on taking advantage of the excitement generated by the Surface RT and Surface Pro announcement. They could have thrown in a free touch keyboard to anyone who pre-ordered. The advertising should have started right after the announcement and gotten bigger as launch day approached. Push for as many pre-order as possible and build excitement for the launch. Actual Launch (Surface RT): By this time all excitement was gone from the initial announcement, except for the Micorsoft faithful. Microsoft should have been ready to sell the Surface in as many markets as possible at launch. The limited market release was a real letdown for a lot of people.  A limited release right after the initial announce is understandable, but not at the official launch of the product. Microsoft overpriced the device and now they are lowering it to what it should have been to start with. The $349 price is within the range I suggested it should be at before pricing was announced. (Surface Tablets: The Price Must Be Right). Limited ordering options online was also a killer. User should have been able to buy the base unit of each device and then add on whatever keyboard they wanted to (this applies more to the Surface Pro).  There should have also been a place where users could order any additional add-ins that they wanted to buy (covers, extra power supplies, etc.) Marketing was better and the dancing “Click In” commercial was cool, but the ads comparing the iPad with Siri should have been on the air from day one of the announcement (or at least the launch).  Consumers want to know why you tablet is better, not just that is has a clickable keyboard and built-in kickstand. They could have also compared it to some of the other mid-range tablets if they had not overprices it to begin with. Stock Applications (Mail, People, Calendar, Music, Video, Reader and IE): This is where Microsoft really blew it. They had all the time in the world to make these applications the best of breed and instead we got applications that seemed thrown together.  Some updates have made these application better, but they are all still lacking in features that should have been there from day one. This did not help to enhance a new users experience any. ** I will admit that the applications that were data driven were first class citizen’s and that makes it even more perplexing why MS could knock it out of the park with the Weather, Travel, Finance, Bing, etc.) and fail so miserably on the core applications users would use the most on a tablet. Desktop on Tablet: The desktop just is so out of place on the tablet  I understand it was needed for Office but think it would have been better to not have the desktop in Windows RT, but instead open up the Office applications in full screen mode, in a desktop shell (same goes for  IE11).That way the user wouldn’t realize they are leaving Metro and going to the desktop. The other option would have been to just not include Office on Windows RT devices. Instead they could have made awesome Widows Store Apps for Word, Excel, OneNote and PowerPoint. In addition, they could have made the stock Mail, People, and Calendar applications contain all the functions that Outlook gives desktop users. Having some of the settings in desktop mode and others under “Change PC Settings” made Windows RT seemed unfinished and rushed to market. What Can Be Done To Make Windows RT Based Tablets Better (At least in my opinion) Either eliminate the desktop all together from Windows RT or at least make the user experience better by hiding the fact the user is running Office/IE in the desktop. Personally I ‘d like them to totally get rid of it and just make awesome Windows Store Application version of Word, Excel PowerPoint & OneNote.  This might also make the OS smaller and give the user more available disk space. I doubt there will ever be a Windows Store App versions of Office, but I still think it is a good idea. Make is so users can easily direct their documents, picture, videos and music to their extra storage and can access these files from the standard libraries.  A user should not have to create a VM on their microSD card or create symbolic links to get this to work properly. Most consumers would not be able to do this. Then users get frustrated when they run out or room on their main storage because nothing is automatically save to their microSD card when saved to libraries.  This is a major bug that needs to be fixed, otherwise Microsoft’s selling point of having a microSD slot is worthless. Allows users to uninstall and re-install any of the Office product that come with the Surface. That way people can free up storage space by uninstalling the Office applications they do not need. Everyone’s needs are different, so make the options flexible. Don’t take up storage space for applications the user will not use. Make the Core applications the “Cream of the Crop” Windows App Store applications. The should set the bar for all other Store applications. Improve performance as much as possible, if it seems to be sluggish on a tablet consumer will not buy it. They need to price the next line of Surface product very aggressive to undercut not only iPad but also Android low end tablets (Nook, Kindle Fire, and Nexus, etc.) Give developers incentives to write quality applications for the devices. Don’t reward developers for cranking out cookie cutter, low quality applications. I’d even suggest Microsoft consider implementing some new store certification guideline to stop these type of applications being published. Allow users to easily move the recover disk “partition between their microSD card and main storage. My Predictions for the Surface RT and Windows RT I honestly think even with all the missteps MS has made since the announcement  about the Surface product line, that they are on the right path. I was excited the Surface tablets when they were announced, and I still am. The truth be told, Windows 8 on a tablet (aka: Windows RT) is better than both iOS and Android. My nephew who is an Apple fan boy told me after he saw and used Windows 8 (he got the beta running on his iPad), that Windows 8 kicked Apples butt as a tablet OS. So there is hope for all Windows RT based tablets. I agree with my nephew and that is why whenever anyone asks me about my Surface, I love showing it off and recommend it. The 6 keys to gaining market share in the tablet market are; Aggressive pricing by both Microsoft and their OEM’s Good quality devices put out by Microsoft and their OEM’s (there are some out there, but not enough) Marketing, Marketing, Marketing from both Microsoft and their OEM’s (Need more ads showing why windows based tablets are better than iPads and Android tablets) Getting Widows tablets in retails stores all over, and giving sales people incentive to sell them. Consumers like to try electronics out before they buy them, and most will listen to what the sales person suggest. Microsoft needs sales people in retail stores directing people to buy windows based tablets over iPads and Android tablets. I think the Microsoft Stores within Best Buy is a good start, but they also need to get prominent displays in Walmart, Target, etc.. Release a smaller form factor Surface, Hopefully the 8”-10” next generation Surface is not a rumor. Make “Surface” the brand name for all Microsoft tablets and hybrid devices that they come out with. They cannot change the name with each new release.  Make Surface synonymous with quality, the same way that iPad  is for Apple. Well, that is my 2 cents on the subject. Let me know your thoughts by leaving a comment below. Soon to follow will be my thought on the Surface Pro, so keep an eye out for it. var addthis_pub="smehaffie"; var addthis_options="email, print, digg, slashdot, delicious, twitter, live, myspace, facebook, google, stumbleupon, newsvine";

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  • Opinion on LastPass's security for the Average Joe [closed]

    - by Rook
    This is borderline on objective/subjective, but I'm posting it here since I'm more interested in objective facts, without going into too much technical details, than I am in user reviews of LastPass. I've always used offline ways for (password / sensitive data) storage, but lately I keep hearing good things about LastPass. Indeed, it is more practical having it always accessible from every computer you're using without syncing and related problems, but the security aspect still troubles me. How (in a nutshell for dummies) does LastPass keep your data secure / can their employees see your data, and what is your opinion for such storage of more than usual keeping of sensitive data (bank PIN codes, some financial / business related stuff and so on - you know, the things that would practically hurt if lost / phished)? What are your opinions of it, and do you trust it for such? Any bad experiences? If someone for example is sniffing your wifi network, would such data be easier than usual to sniff out?

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  • Announcing StorageTek VSM 6 and VLE Capacity Increase

    - by uwes
    Announcing Increased Capacity on StorageTek Virtual Storage Manager System 6 (VSM6) and StorageTek Virtual Library Extension (VLE)! StorageTek Virtual Storage Manager System 6 (VSM 6) and the StorageTek Virtual Library Extension (VLE) makes data management simple for the mainframe data center - Simple to deploy, simple to manage, and simple to scale.  With this announcement, StorageTek VSM 6 as well as StorageTek VLE capacity scaling increases by 33% for StorageTek VSM 6 and 21% for StorageTek VLE.  This significant capacity increase can provide increased consolidation potential for multiple VSM 4/5’s into a single VSM 6. In addition to the StorageTek VSM 6 and VLE capacity increases we are announcing End of Life (EOL) for previous generation StorageTek VSM 6 and VLE part numbers.   Please read the Sales Bulletin on Oracle HW TRC for more details. (If you are not registered on Oracle HW TRC, click here ... and follow the instructions..) For More Information Go To: Oracle.com Tape Page Oracle Technology Network Tape Page

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  • Call for Papers Ends March 21

    - by jack.flynn
    Have Something to Say? Better Say So Now. The Call for Papers for Oracle OpenWorld and the Develop Stream of JavaOne+Develop ends at midnight on Sunday, March 21. So if you want to be a part of the most influential IT events of the year, don't let this chance pass you by. This year offers opportunities to speak out about some new subjects: Oracle OpenWorld adds a whole new Server and Storage Systems stream, including Sun servers, Sun storage and tape, and Oracle Solaris operating system. And the Develop audience should be larger and more energetic than ever now that it's co-located with JavaOne. If you have something important to say, this is the time to let us know. Find all the information on the Call for Papers process, timeline, and guidelines here.

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  • How could RDBMSes be considered a fad?

    - by StuperUser
    Completing my Computing A-level in 2003 and getting a degree in Computing in 2007, and learning my trade in a company with a lot of SQL usage, I was brought up on the idea of Relational Databases being used for storage. So, despite being relatively new to development, I was taken-aback to read a comment (on Is LinqPad site quote "Tired of querying in antiquated SQL?" accurate? ) that said: [Some devs] despise [SQL] and think that it and RDBMS are a fad Obviously, a competent dev will use the right tool for the right job and won't create a relational database when e.g. flat file or another solution for storage is appropriate, but RDBMs are useful in a massive number of circumstances, so how could they be considered a fad?

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  • Awesome new feature for HCC

    - by Steve Tunstall
    I've talked about HCC (Hybrid Columnar Compression) before. This is Oracle's built-in compression feature, free of charge in 11Gr2, that allows a CRAZY amount of compression on historical data inside an Oracle database. It only works if the database is being stored in a ZFSSA, Exadata or Axiom. You can read all about it in this whitepaper, which shows the huge value of HCC when used with the ZFSSA. http://www.oracle.com/technetwork/articles/servers-storage-admin/perf-hybrid-columnar-compression-1689701.html Now, even better, Oracle has announced  a great new feature in Oracle 12c called "Automatic Data Optimization". This allows one to setup HCC to AUTOMATICALLY compress data AS IT AGES.  So this is now ILM all built into the Oracle database. It's free for crying out loud. It just needs to be sitting on Oracle storage, such as the ZFSSA, Exadata or Axiom.  Read about ADO here: http://www.oracle.com/technetwork/database/automatic-data-optimization-wp-12c-1896120.pdf?ssSourceSiteId=ocomen

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  • Database Machine gyakorlati tapasztalatok!

    - by Fekete Zoltán
    Ketto héttel ezelott gyakorlati tapasztalatokat szereztünk egy magyarországon muködo vállalat adattárházával egy igazi Database Machine / Exadata környezetben, egy Sun Oracle Database Machine Half Rack kiépítéssel. Az eredmények valóban lenyugözöek. Az Exadata Storage izgalmas és egyedi tulajdonságai: Smart Scan, Smart Flash Cache, Storage Index, tömörítés: Exadata Hybrid Columnar Compression, a hihetetlen mértéku párhuzamosság olyan teljesítmény elonyhöz juttatja a felhasználót, ami szemelkerekedést, ujjongást és hosszantartó belso mosolyt eredményez. Hogy ez hasznos-e az Ön és adatbázis környezete egészségére nézve? :) Kérdezze meg orvosát, gyógyszerészét és a white paper leírásokat, továbbá publikált ügyfél történeteket. A technikai és kereskedelmi részletekrol kérdezzen engem. :) A holnapi (2010. máricius 24. szerda) eloadáson a HOUG Konferencián személyesen is meghallgathatók ezek a gyakorlati tapasztalatok, authentikus forrásból. Hasonlóan szép napokat kívánok mindenkinek!

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  • SQL SERVER – Weekly Series – Memory Lane – #032

    - by Pinal Dave
    Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Complete Series of Database Coding Standards and Guidelines SQL SERVER Database Coding Standards and Guidelines – Introduction SQL SERVER – Database Coding Standards and Guidelines – Part 1 SQL SERVER – Database Coding Standards and Guidelines – Part 2 SQL SERVER Database Coding Standards and Guidelines Complete List Download Explanation and Example – SELF JOIN When all of the data you require is contained within a single table, but data needed to extract is related to each other in the table itself. Examples of this type of data relate to Employee information, where the table may have both an Employee’s ID number for each record and also a field that displays the ID number of an Employee’s supervisor or manager. To retrieve the data tables are required to relate/join to itself. Insert Multiple Records Using One Insert Statement – Use of UNION ALL This is very interesting question I have received from new developer. How can I insert multiple values in table using only one insert? Now this is interesting question. When there are multiple records are to be inserted in the table following is the common way using T-SQL. Function to Display Current Week Date and Day – Weekly Calendar Straight blog post with script to find current week date and day based on the parameters passed in the function.  2008 In my beginning years, I have almost same confusion as many of the developer had in their earlier years. Here are two of the interesting question which I have attempted to answer in my early year. Even if you are experienced developer may be you will still like to read following two questions: Order Of Column In Index Order of Conditions in WHERE Clauses Example of DISTINCT in Aggregate Functions Have you ever used DISTINCT with the Aggregation Function? Here is a simple example about how users can do it. Create a Comma Delimited List Using SELECT Clause From Table Column Straight to script example where I explained how to do something easy and quickly. Compound Assignment Operators SQL SERVER 2008 has introduced new concept of Compound Assignment Operators. Compound Assignment Operators are available in many other programming languages for quite some time. Compound Assignment Operators is operator where variables are operated upon and assigned on the same line. PIVOT and UNPIVOT Table Examples Here is a very interesting question – the answer to the question can be YES or NO both. “If we PIVOT any table and UNPIVOT that table do we get our original table?” Read the blog post to get the explanation of the question above. 2009 What is Interim Table – Simple Definition of Interim Table The interim table is a table that is generated by joining two tables and not the final result table. In other words, when two tables are joined they create an interim table as resultset but the resultset is not final yet. It may be possible that more tables are about to join on the interim table, and more operations are still to be applied on that table (e.g. Order By, Having etc). Besides, it may be possible that there is no interim table; sometimes final table is what is generated when the query is run. 2010 Stored Procedure and Transactions If Stored Procedure is transactional then, it should roll back complete transactions when it encounters any errors. Well, that does not happen in this case, which proves that Stored Procedure does not only provide just the transactional feature to a batch of T-SQL. Generate Database Script for SQL Azure When talking about SQL Azure the most common complaint I hear is that the script generated from stand-along SQL Server database is not compatible with SQL Azure. This was true for some time for sure but not any more. If you have SQL Server 2008 R2 installed you can follow the guideline below to generate a script which is compatible with SQL Azure. Convert IN to EXISTS – Performance Talk It is NOT necessary that every time when IN is replaced by EXISTS it gives better performance. However, in our case listed above it does for sure give better performance. You can read about this subject in the associated blog post. Subquery or Join – Various Options – SQL Server Engine Knows the Best Every single time whenever there is a performance tuning exercise, I hear the conversation from developer where some prefer subquery and some prefer join. In this two part blog post, I explain the same in the detail with examples. Part 1 | Part 2 Merge Operations – Insert, Update, Delete in Single Execution MERGE is a new feature that provides an efficient way to do multiple DML operations. In earlier versions of SQL Server, we had to write separate statements to INSERT, UPDATE, or DELETE data based on certain conditions; however, at present, by using the MERGE statement, we can include the logic of such data changes in one statement that even checks when the data is matched and then just update it, and similarly, when the data is unmatched, it is inserted. 2011 Puzzle – Statistics are not updated but are Created Once Here is the quick scenario about my setup. Create Table Insert 1000 Records Check the Statistics Now insert 10 times more 10,000 indexes Check the Statistics – it will be NOT updated – WHY? Question to You – When to use Function and When to use Stored Procedure Personally, I believe that they are both different things - they cannot be compared. I can say, it will be like comparing apples and oranges. Each has its own unique use. However, they can be used interchangeably at many times and in real life (i.e., production environment). I have personally seen both of these being used interchangeably many times. This is the precise reason for asking this question. 2012 In year 2012 I had two interesting series ran on the blog. If there is no fun in learning, the learning becomes a burden. For the same reason, I had decided to build a three part quiz around SEQUENCE. The quiz was to identify the next value of the sequence. I encourage all of you to take part in this fun quiz. Guess the Next Value – Puzzle 1 Guess the Next Value – Puzzle 2 Guess the Next Value – Puzzle 3 Guess the Next Value – Puzzle 4 Simple Example to Configure Resource Governor – Introduction to Resource Governor Resource Governor is a feature which can manage SQL Server Workload and System Resource Consumption. We can limit the amount of CPU and memory consumption by limiting /governing /throttling on the SQL Server. If there are different workloads running on SQL Server and each of the workload needs different resources or when workloads are competing for resources with each other and affecting the performance of the whole server resource governor is a very important task. Tricks to Replace SELECT * with Column Names – SQL in Sixty Seconds #017 – Video  Retrieves unnecessary columns and increases network traffic When a new columns are added views needs to be refreshed manually Leads to usage of sub-optimal execution plan Uses clustered index in most of the cases instead of using optimal index It is difficult to debug SQL SERVER – Load Generator – Free Tool From CodePlex The best part of this SQL Server Load Generator is that users can run multiple simultaneous queries again SQL Server using different login account and different application name. The interface of the tool is extremely easy to use and very intuitive as well. A Puzzle – Swap Value of Column Without Case Statement Let us assume there is a single column in the table called Gender. The challenge is to write a single update statement which will flip or swap the value in the column. For example if the value in the gender column is ‘male’ swap it with ‘female’ and if the value is ‘female’ swap it with ‘male’. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Microsoft and the open source community

    - by Charles Young
    For the last decade, I have repeatedly, in my imitable Microsoft fan boy style, offered an alternative view to commonly held beliefs about Microsoft's stance on open source licensing.  In earlier times, leading figures in Microsoft were very vocal in resisting the idea that commercial licensing is outmoded or morally reprehensible.  Many people interpreted this as all-out corporate opposition to open source licensing.  I never read it that way. It is true that I've met individual employees of Microsoft who are antagonistic towards FOSS (free and open source software), but I've met more who are supportive or at least neutral on the subject.  In any case, individual attitudes of employees don't necessarily reflect a corporate stance.  The strongest opposition I've encountered has actually come from outside the company.  It's not a charitable thought, but I sometimes wonder if there are people in the .NET community who are opposed to FOSS simply because they believe, erroneously, that Microsoft is opposed. Here, for what it is worth, are the points I've repeated endlessly over the years and which have often been received with quizzical scepticism. a)  A decade ago, Microsoft's big problem was not FOSS per se, or even with copyleft.  The thing which really kept them awake at night was the fear that one day, someone might find, deep in the heart of the Windows code base, some code that should not be there and which was published under GPL.  The likelihood of this ever happening has long since faded away, but there was a time when MS was running scared.  I suspect this is why they held out for a while from making Windows source code open to inspection.  Nowadays, as an MVP, I am positively encouraged to ask to see Windows source. b)  Microsoft has never opposed the open source community.  They have had problems with specific people and organisations in the FOSS community.  Back in the 1990s, Richard Stallman gave time and energy to a successful campaign to launch antitrust proceedings against Microsoft.  In more recent times, the negative attitude of certain people to Microsoft's submission of two FOSS licences to the OSI (both of which have long since been accepted), and the mad scramble to try to find any argument, however tenuous, to block their submission was not, let us say, edifying. c) Microsoft has never, to my knowledge, written off the FOSS model.  They certainly don't agree that more traditional forms of licensing are inappropriate or immoral, and they've always been prepared to say so.  One reason why it was so hard to convince people that Microsoft is not rabidly antagonistic towards FOSS licensing is that so many people think they have no involvement in open source.  A decade ago, there was virtually no evidence of any such involvement.  However, that was a long time ago.  Quietly over the years, Microsoft has got on with the job of working out how to make use of FOSS licensing and how to support the FOSS community.  For example, as well as making increasingly extensive use of Github, they run an important FOSS forge (CodePlex) on which they, themselves, host many hundreds of distinct projects.  The total count may even be in the thousands now.  I suspect there is a limit of about 500 records on CodePlex searches because, for the past few years, whenever I search for Microsoft-specific projects on CodePlex, I always get approx. 500 hits.  Admittedly, a large volume of the stuff they publish under FOSS licences amounts to code samples, but many of those 'samples' have grown into useful and fully featured frameworks, libraries and tools. All this is leading up to the observation that yesterday's announcement by Scott Guthrie marks a significant milestone and should not go unnoticed.  If you missed it, let me summarise.   From the first release of .NET, Microsoft has offered a web development framework called ASP.NET.  The core libraries are included in the .NET framework which is released free of charge, but which is not open source.   However, in recent years, the number of libraries that constitute ASP.NET have grown considerably.  Today, most professional ASP.NET web development exploits the ASP.NET MVC framework.  This, together with several other important parts of the ASP.NET technology stack, is released on CodePlex under the Apache 2.0 licence.   Hence, today, a huge swathe of web development on the .NET/Azure platform relies four-square on the use of FOSS frameworks and libraries. Yesterday, Scott Guthrie announced the next stage of ASP.NET's journey towards FOSS nirvana.  This involves extending ASP.NET's FOSS stack to include Web API and the MVC Razor view engine which is rapidly becoming the de facto 'standard' for building web pages in ASP.NET.  However, perhaps the more important announcement is that the ASP.NET team will now accept and review contributions from the community.  Scott points out that this model is already in place elsewhere in Microsoft, and specifically draws attention to development of the Windows Azure SDKs.  These SDKs are central to Azure development.   The .NET and Java SDKs are published under Apache 2.0 on Github and Microsoft is open to community contributions.  Accepting contributions is a more profound move than simply releasing code under FOSS licensing.  It means that Microsoft is wholeheartedly moving towards a full-blooded open source approach for future evolution of some of their central and most widely used .NET and Azure frameworks and libraries.  In conjunction with Scott's announcement, Microsoft has also released Git support for CodePlex (at long last!) and, perhaps more importantly, announced significant new investment in their own FOSS forge. Here at Solidsoft we have several reasons to be very interested in Scott's announcement. I'll draw attention to one of them.  Earlier this year we wrote the initial version of a new UK Government web application called CloudStore.  CloudStore provides a way for local and central government to discover and purchase applications and services. We wrote the web site using ASP.NET MVC which is FOSS.  However, this point has been lost on the ladies and gentlemen of the press and, I suspect, on some of the decision makers on the government side.  They announced a few weeks ago that future versions of CloudStore will move to a FOSS framework, clearly oblivious of the fact that it is already built on a FOSS framework.  We are, it is fair to say, mildly irked by the uninformed and badly out-of-date assumption that “if it is Microsoft, it can't be FOSS”.  Old prejudices live on.

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  • Backup Your Windows Home Server Off-Site with Asus Webstorage

    - by Mysticgeek
    Windows Home Server lets you backup machines on your network easily. But what about backing up the server data? Today we take a look at ASUS WebStorage for Windows Home Server, which provides you with secure off-site backup for WHS. To use the ASUS WebStorage service you’ll need to sign up for a free account. It offers 1GB of free storage, then you can purchase an unlimited backup package for $39.99 for a year subscription. Note: They also offer online storage for individual PCs as well. Install ASUS WebStorage for WHS Browse to your shared folders on the server and open the Add-Ins folder and copy over the WHSConnectorSetup2.2.4.088.msi file (link below) then close out of the folder. Now launch Windows Home Server Console from one of the computers on your network, click Settings, then Add-ins. Under Available Add-ins click the Available tab and you’ll see the Asus WebStorage installer file we just copied over. Click the Install button. Installation kicks off and when it’s complete, you’ll need to close out of the console and reconnect. Using ASUS WebStorage WHS Connector  When you reconnect to WHS Console, scroll over to the ASUS WebStorage icon and click on Settings. Now log into your ASUS account… Now select the folders you want to backup to the WebStorage service. Select the radio button next to Enable to initialize the backup process… The backup process begins. You can change which folders are backed up simply by disabling the backup process, uncheck the folder(s), then enable the backup again. ASUS WebStorage Site After you have files backed up to the ASUS site, log into your account, and your presented with an overview of the amount of storage you’re using. It also shows what type of files are taking certain amounts of space.   You can browse through your backed up files and folders. It allows you to share and sync backed up data as well. Navigate to the file you want and you can easily download it by clicking on it, or share it out by clicking the share link below it. If you choose to share it, you’re provided with a link to the file to send out to other users.   Conclusion Users of Windows Home Server have been looking for an inexpensive cloud backup solution for quite some time. There are services such as JungleDisk, KeepVault, Wuala…etc. These services probably do a better job, but can start getting expensive once you start uploading a GBs of data. Another disappointment of ASUS WebStorage is you can only backup your WHS shares (from what we’ve been able to determine), it’s an “all or nothing” type of thing. You cannot go in and select individual files and folders. The initial upload speeds can be a bit slow as well, although that might have something to do with limited upload speeds on the DSL connection we used to test it. Retrieving your data from the ASUS site is a breeze though, and all the data files are organized quite well. The WHS Addin is very easy to install and use. If you’re looking for an off-site solution to backup your WHS data, you can test out ASUS WebStorage for free with a 1GB limit. This is good for testing the service and it might be exactly what you’re looking for. Other users may want a more advanced solution like KeepVault or CloudBerry…which is a front end for Amazon S3 storage. Download ASUS WebStorage WHS Addin Other WHS Offsite Backup Solutions CloudBerry, JungleDisk, KeepVault, Wuala Similar Articles Productive Geek Tips Restore Files from Backups on Windows Home ServerGMedia Blog: Setting Up a Windows Home ServerCreate A Windows Home Server Home Computer Restore DiscRemove a Network Computer from Windows Home ServerShare Ubuntu Home Directories using Samba TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Gadfly is a cool Twitter/Silverlight app Enable DreamScene in Windows 7 Microsoft’s “How Do I ?” Videos Home Networks – How do they look like & the problems they cause Check Your IMAP Mail Offline In Thunderbird Follow Finder Finds You Twitter Users To Follow

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