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  • What are the typical methods used to scale up/out email storage servers?

    - by nareshov
    Hi, What I've tried: I have two email storage architectures. Old and new. Old: courier-imapds on several (18+) 1TB-storage servers. If one of them show signs of running out of disk space, we migrate a few email accounts to another server. the servers don't have replicas. no backups either. New: dovecot2 on a single huge server with 16TB (SATA) storage and a few SSDs we store fresh mails on the SSDs and run a doveadm purge to move mails older than a day to the SATA disks there is an identical server which has a max-15min-old rsync backup from the primary server higher-ups/management wanted to pack in as much storage as possible per server in order to minimise the cost of SSDs per server the rsync'ing is done because GlusterFS wasn't replicating well under that high small/random-IO. scaling out was expected to be done with provisioning another pair of such huge servers on facing disk-crunch issues like in the old architecture, manual moving of email accounts would be done. Concerns/doubts: I'm not convinced with the synchronously-replicated filesystem idea works well for heavy random/small-IO. GlusterFS isn't working for us yet, I'm not sure if there's another filesystem out there for this use case. The idea was to keep identical pairs and use DNS round-robin for email delivery and IMAP/POP3 access. And if one the servers went down for whatever reasons (planned/unplanned), we'd move the IP to the other server in the pair. In filesystems like Lustre, I get the advantage of a single namespace whereby I do not have to worry about manually migrating accounts around and updating MAILHOME paths and other metadata/data. Questions: What are the typical methods used to scale up/out with the traditional software (courier-imapd / dovecot)? Do traditional software that store on a locally mounted filesystem pose a roadblock to scale out with minimal "problems"? Does one have to re-write (parts of) these to work with an object-storage of some sort - such as OpenStack object storage?

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  • How to restore your production database without needing additional storage

    - by David Atkinson
    Production databases can get very large. This in itself is to be expected, but when a copy of the database is needed the database must be restored, requiring additional and costly storage.  For example, if you want to give each developer a full copy of your production server, you'll need n times the storage cost for your n-developer team. The same is true for any test databases that are created during the course of your project lifecycle. If you've read my previous blog posts, you'll be aware that I've been focusing on the database continuous integration theme. In my CI setup I create a "production"-equivalent database directly from its source control representation, and use this to test my upgrade scripts. Despite this being a perfectly valid and practical thing to do as part of a CI setup, it's not the exact equivalent to running the upgrade script on a copy of the actual production database. So why shouldn't I instead simply restore the most recent production backup as part of my CI process? There are two reasons why this would be impractical. 1. My CI environment isn't an exact copy of my production environment. Indeed, this would be the case in a perfect world, and it is strongly recommended as a good practice if you follow Jez Humble and David Farley's "Continuous Delivery" teachings, but in practical terms this might not always be possible, especially where storage is concerned. It may just not be possible to restore a huge production database on the environment you've been allotted. 2. It's not just about the storage requirements, it's also the time it takes to do the restore. The whole point of continuous integration is that you are alerted as early as possible whether the build (yes, the database upgrade script counts!) is broken. If I have to run an hour-long restore each time I commit a change to source control I'm just not going to get the feedback quickly enough to react. So what's the solution? Red Gate has a technology, SQL Virtual Restore, that is able to restore a database without using up additional storage. Although this sounds too good to be true, the explanation is quite simple (although I'm sure the technical implementation details under the hood are quite complex!) Instead of restoring the backup in the conventional sense, SQL Virtual Restore will effectively mount the backup using its HyperBac technology. It creates a data and log file, .vmdf, and .vldf, that becomes the delta between the .bak file and the virtual database. This means that both read and write operations are permitted on a virtual database as from SQL Server's point of view it is no different from a conventional database. Instead of doubling the storage requirements upon a restore, there is no 'duplicate' storage requirements, other than the trivially small virtual log and data files (see illustration below). The benefit is magnified the more databases you mount to the same backup file. This technique could be used to provide a large development team a full development instance of a large production database. It is also incredibly easy to set up. Once SQL Virtual Restore is installed, you simply run a conventional RESTORE command to create the virtual database. This is what I have running as part of a nightly "release test" process triggered by my CI tool. RESTORE DATABASE WidgetProduction_virtual FROM DISK=N'C:\WidgetWF\ProdBackup\WidgetProduction.bak' WITH MOVE N'WidgetProduction' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_WidgetProduction_Virtual.vmdf', MOVE N'WidgetProduction_log' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_log_WidgetProduction_Virtual.vldf', NORECOVERY, STATS=1, REPLACE GO RESTORE DATABASE mydatabase WITH RECOVERY   Note the only change from what you would do normally is the naming of the .vmdf and .vldf files. SQL Virtual Restore intercepts this by monitoring the extension and applies its magic, ensuring the 'virtual' restore happens rather than the conventional storage-heavy restore. My automated release test then applies the upgrade scripts to the virtual production database and runs some validation tests, giving me confidence that were I to run this on production for real, all would go smoothly. For illustration, here is my 8Gb production database: And its corresponding backup file: Here are the .vldf and .vmdf files, which represent the only additional used storage for the new database following the virtual restore.   The beauty of this product is its simplicity. Once it is installed, the interaction with the backup and virtual database is exactly the same as before, as the clever stuff is being done at a lower level. SQL Virtual Restore can be downloaded as a fully functional 14-day trial. Technorati Tags: SQL Server

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  • How to restore your production database without needing additional storage

    - by David Atkinson
    Production databases can get very large. This in itself is to be expected, but when a copy of the database is needed the database must be restored, requiring additional and costly storage.  For example, if you want to give each developer a full copy of your production server, you’ll need n times the storage cost for your n-developer team. The same is true for any test databases that are created during the course of your project lifecycle. If you’ve read my previous blog posts, you’ll be aware that I’ve been focusing on the database continuous integration theme. In my CI setup I create a “production”-equivalent database directly from its source control representation, and use this to test my upgrade scripts. Despite this being a perfectly valid and practical thing to do as part of a CI setup, it’s not the exact equivalent to running the upgrade script on a copy of the actual production database. So why shouldn’t I instead simply restore the most recent production backup as part of my CI process? There are two reasons why this would be impractical. 1. My CI environment isn’t an exact copy of my production environment. Indeed, this would be the case in a perfect world, and it is strongly recommended as a good practice if you follow Jez Humble and David Farley’s “Continuous Delivery” teachings, but in practical terms this might not always be possible, especially where storage is concerned. It may just not be possible to restore a huge production database on the environment you’ve been allotted. 2. It’s not just about the storage requirements, it’s also the time it takes to do the restore. The whole point of continuous integration is that you are alerted as early as possible whether the build (yes, the database upgrade script counts!) is broken. If I have to run an hour-long restore each time I commit a change to source control I’m just not going to get the feedback quickly enough to react. So what’s the solution? Red Gate has a technology, SQL Virtual Restore, that is able to restore a database without using up additional storage. Although this sounds too good to be true, the explanation is quite simple (although I’m sure the technical implementation details under the hood are quite complex!) Instead of restoring the backup in the conventional sense, SQL Virtual Restore will effectively mount the backup using its HyperBac technology. It creates a data and log file, .vmdf, and .vldf, that becomes the delta between the .bak file and the virtual database. This means that both read and write operations are permitted on a virtual database as from SQL Server’s point of view it is no different from a conventional database. Instead of doubling the storage requirements upon a restore, there is no ‘duplicate’ storage requirements, other than the trivially small virtual log and data files (see illustration below). The benefit is magnified the more databases you mount to the same backup file. This technique could be used to provide a large development team a full development instance of a large production database. It is also incredibly easy to set up. Once SQL Virtual Restore is installed, you simply run a conventional RESTORE command to create the virtual database. This is what I have running as part of a nightly “release test” process triggered by my CI tool. RESTORE DATABASE WidgetProduction_Virtual FROM DISK=N'D:\VirtualDatabase\WidgetProduction.bak' WITH MOVE N'WidgetProduction' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_WidgetProduction_Virtual.vmdf', MOVE N'WidgetProduction_log' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_log_WidgetProduction_Virtual.vldf', NORECOVERY, STATS=1, REPLACE GO RESTORE DATABASE WidgetProduction_Virtual WITH RECOVERY   Note the only change from what you would do normally is the naming of the .vmdf and .vldf files. SQL Virtual Restore intercepts this by monitoring the extension and applies its magic, ensuring the ‘virtual’ restore happens rather than the conventional storage-heavy restore. My automated release test then applies the upgrade scripts to the virtual production database and runs some validation tests, giving me confidence that were I to run this on production for real, all would go smoothly. For illustration, here is my 8Gb production database: And its corresponding backup file: Here are the .vldf and .vmdf files, which represent the only additional used storage for the new database following the virtual restore.   The beauty of this product is its simplicity. Once it is installed, the interaction with the backup and virtual database is exactly the same as before, as the clever stuff is being done at a lower level. SQL Virtual Restore can be downloaded as a fully functional 14-day trial. Technorati Tags: SQL Server

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  • How to restore your production database without needing additional storage

    - by David Atkinson
    Production databases can get very large. This in itself is to be expected, but when a copy of the database is needed the database must be restored, requiring additional and costly storage.  For example, if you want to give each developer a full copy of your production server, you'll need n times the storage cost for your n-developer team. The same is true for any test databases that are created during the course of your project lifecycle. If you've read my previous blog posts, you'll be aware that I've been focusing on the database continuous integration theme. In my CI setup I create a "production"-equivalent database directly from its source control representation, and use this to test my upgrade scripts. Despite this being a perfectly valid and practical thing to do as part of a CI setup, it's not the exact equivalent to running the upgrade script on a copy of the actual production database. So why shouldn't I instead simply restore the most recent production backup as part of my CI process? There are two reasons why this would be impractical. 1. My CI environment isn't an exact copy of my production environment. Indeed, this would be the case in a perfect world, and it is strongly recommended as a good practice if you follow Jez Humble and David Farley's "Continuous Delivery" teachings, but in practical terms this might not always be possible, especially where storage is concerned. It may just not be possible to restore a huge production database on the environment you've been allotted. 2. It's not just about the storage requirements, it's also the time it takes to do the restore. The whole point of continuous integration is that you are alerted as early as possible whether the build (yes, the database upgrade script counts!) is broken. If I have to run an hour-long restore each time I commit a change to source control I'm just not going to get the feedback quickly enough to react. So what's the solution? Red Gate has a technology, SQL Virtual Restore, that is able to restore a database without using up additional storage. Although this sounds too good to be true, the explanation is quite simple (although I'm sure the technical implementation details under the hood are quite complex!) Instead of restoring the backup in the conventional sense, SQL Virtual Restore will effectively mount the backup using its HyperBac technology. It creates a data and log file, .vmdf, and .vldf, that becomes the delta between the .bak file and the virtual database. This means that both read and write operations are permitted on a virtual database as from SQL Server's point of view it is no different from a conventional database. Instead of doubling the storage requirements upon a restore, there is no 'duplicate' storage requirements, other than the trivially small virtual log and data files (see illustration below). The benefit is magnified the more databases you mount to the same backup file. This technique could be used to provide a large development team a full development instance of a large production database. It is also incredibly easy to set up. Once SQL Virtual Restore is installed, you simply run a conventional RESTORE command to create the virtual database. This is what I have running as part of a nightly "release test" process triggered by my CI tool. RESTORE DATABASE WidgetProduction_virtual FROM DISK=N'C:\WidgetWF\ProdBackup\WidgetProduction.bak' WITH MOVE N'WidgetProduction' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_WidgetProduction_Virtual.vmdf', MOVE N'WidgetProduction_log' TO N'C:\WidgetWF\ProdBackup\WidgetProduction_log_WidgetProduction_Virtual.vldf', NORECOVERY, STATS=1, REPLACE GO RESTORE DATABASE mydatabase WITH RECOVERY   Note the only change from what you would do normally is the naming of the .vmdf and .vldf files. SQL Virtual Restore intercepts this by monitoring the extension and applies its magic, ensuring the 'virtual' restore happens rather than the conventional storage-heavy restore. My automated release test then applies the upgrade scripts to the virtual production database and runs some validation tests, giving me confidence that were I to run this on production for real, all would go smoothly. For illustration, here is my 8Gb production database: And its corresponding backup file: Here are the .vldf and .vmdf files, which represent the only additional used storage for the new database following the virtual restore.   The beauty of this product is its simplicity. Once it is installed, the interaction with the backup and virtual database is exactly the same as before, as the clever stuff is being done at a lower level. SQL Virtual Restore can be downloaded as a fully functional 14-day trial. Technorati Tags: SQL Server

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  • Simple Scripting for your Exalogic Storage

    - by Trond Strømme
    As part of my job in Oracle ACS (Advanced Customer Services) I'm handling lots of different systems and customers. Among the recent systems I worked with have been Oracle's Exalogic engineered systems. One of the things I'd never had much exposure to as a system developer/architect/middleware guy/Java dude has been storage; outside of consuming it for my photography needs.. Well, I'm always ready for a new challenge... I'd downloaded the 7000 series storage simulator when it was released in the good old Sun days, found it fun and instructive to play around with, but as I never touched storage in any way (besides consuming it..) I forgot about it. A couple of years ago when I started working with Exalogic engineered systems it again came into light as an invaluable learning and testing tool for the embedded storage in an Exalogic;  Oracle's Sun ZFS Storage 7320 Appliance.  aaaanyway... I've been "booted" into a part-time role as the interim storage/system admin/middleware/Java guy for a client and found I needed to create the occasional report or summary or whatever.. of what's using the storage in the 7320 (as default configured for an Exalogic, 40T of disk in a mirrored configuration, yielding 18T of actual space.) Reading the nice documentation and some articles on the Oracle Technology Network I saw great possibilities with the embedded ECMAScript3/JavaScript engine in the 7000 series.  In my personal opinion anyone who's dealing with Exalogic administration, or exposed to any of the 7000 series of storage appliances and servers that Oracle offers should have a VirtualBox instance of it kicking around. For development and testing it's a fantastic tool. (It can save you from explaining (most) of the embarrassing FAILS you can do if you test something in a production system to your management...) So download, and install.  A small sidestep, if after firing up the 7000 series simulator in VirtualBox you've forgotten what it's IP address is, the following will sort you out if you log in directly via the running VirtualBox VM. So in my case I can ssh to 192.168.56.101 or point a browser to https://192.168.56.101:215 to log into the storage appliance. One simple way of executing a script on the 7320 is to ssh to the device and redirecting a file with the script in it to ssh. ssh [email protected] < myscript.js One question I got from my client and the people who will take over the systems was: "how can we see the quotas and allocations for all projects/shares in one easy go so we don't have to go navigating around in the BUI for all the hundreds of shares the 7320 is hosting just to check if anything is running dry?" Easy! JavaScript time, VirtualBox and emacs! //NOTE! this script is available 'as is' It has ben run on a couple of 7320's, (running 2010.08.17.3.0,1-1.25 & // 2011.04.24.1.0,1-1.8) a 7420 and the VB image, but I personally //offer no guarantee whatsoever that it won't make your server topple, catch fire or in any way go pear shaped.. //run at your own risk or learn from my code and or mistakes.. script run('cd /'); run('shares'); //get all projects: proj = list(); function spaceToGig(bytes){ return bytes/1073741824; //convert bytes to GB } function fullInPercent(quota, space_data){ tmp = (space_data/quota)*100; return tmp; } //print header, slightly good looking printf(" %s/%-15s %8s(GB) %7s(GB) %5s(GB) %7s(GB) %3s\n","Project", "Share","Quota","Ref", "Snap", "Total","%full"); printf("-------------------------------------------------------------------------------\n") //for each project, get all shares. check for quota and calculate percentage and human readable figures.. for (i=0;i<proj.length;i++){ run('select ' + proj[i]); //get all shares for a project var pshares = list(); //for each share get quota properties for (j=0;j<pshares.length;j++){ run('select ' + pshares[j]); quota = get('quota'); //properties associated with a share or inherited from a project spaceData = get('space_data'); spaceSnap = get('space_snapshots'); spaceTotal = get('space_total'); if(quota>0){ //has quota printf(" %s/%-15s \t%4.2fGB\t%.2fGB\t%.2fGB\t%.2fGB\t%5.2f%%\n",proj[i], pshares[j],spaceToGig(quota),spaceToGig(spaceData),spaceToGig(spaceSnap),spaceToGig(spaceTotal),fullInPercent(quota,spaceTotal)); }else{ //no quota printf(" %s/%-15s \t%8s\t%.2fGB\t%.2fGB\t%.2fGB\t%s\n",proj[i],pshares[j], "N/A", spaceToGig(spaceData),spaceToGig(spaceSnap),spaceToGig(spaceTotal),"N/A"); } run('cd ..'); } run('done'); } The resulting output should look something like this: Project/Share Quota(GB) Ref(GB) Snap(GB) Total(GB) %full ------------------------------------------------------------------------------- ACSExalogicSystem/domains N/A 0.04GB 0.00GB 0.04GB N/A ACSExalogicSystem/logs N/A 0.01GB 0.00GB 0.01GB N/A ACSExalogicSystem/nodemgrs N/A 0.00GB 0.00GB 0.00GB N/A ACSExalogicSystem/stores N/A 0.04GB 0.00GB 0.04GB N/A ***_dev/FMW_***_1 133GB 4.24GB 0.01GB 4.25GB 3.19% ***_dev/FMW_***_2 N/A 4.25GB 0.01GB 4.26GB N/A ***_dev/applications 10GB 0.00GB 0.00GB 0.00GB 0.00% ***_dev/domains 50GB 10.75GB 3.55GB 14.30GB 28.61% ***_dev/logs 20GB 0.32GB 0.01GB 0.33GB 1.66% ***_dev/softwaredepot 20GB 4.15GB 0.00GB 4.15GB 20.73% ***_dev/stores 20GB 0.01GB 0.00GB 0.01GB 0.05% ###_dev/FMW_###_1 400GB 17.63GB 0.12GB 17.75GB 4.44% ###_dev/applications N/A 0.00GB 0.00GB 0.00GB N/A ###_dev/domains 120GB 14.21GB 5.53GB 19.74GB 16.45% ###_dev/logs 15GB 0.00GB 0.00GB 0.00GB 0.00% ###_dev/softwaredepot 250GB 73.55GB 0.02GB 73.57GB 29.43% …snip My apologies if the output is a bit mis-aligned here and there, I only bothered making it look good, not perfect :/ I also removed some of the project names (*,#)

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  • Windows 8.1 Insufficient storage available to create shadow copy

    - by Bob.at.SBS
    [Note: After I entered the problem statement, I found this question, which is apparently the same problem. Maybe one of us will get a good answer...] I have used the "Windows 7 File Recovery" tool under Windows 8 to create system image backups to an external USB hard drive. I built a new Windows 8.1 machine, and I want to create my first system image backup of that machine to the same USB hard drive. The "Windows 7 File Recovery" tool is gone in Windows 8.1, but wbAdmin is alive and well: wbAdmin start backup -backupTarget:\\?\Volume{2a2b...994f} -allCritical -quiet fails with this text displayed: wbadmin 1.0 - Backup command-line tool (C) Copyright 2013 Microsoft Corporation. All rights reserved. Retrieving volume information... This will back up (EFI System Partition),(C:),Recovery (300.00 MB) to \?\Volume {2a2b1255-3a86-11e3-be86-b8ca3a83994f}. The backup operation to F: is starting. Creating a shadow copy of the volumes specified for backup... Summary of the backup operation: The backup operation stopped before completing. The backup operation stopped before completing. Detailed error: ERROR - A Volume Shadow Copy Service operation error has occurred: (0x8004231f) Insufficient storage available to create either the shadow copy storage file or other shadow copy data. The EFI System Partition is 100 MB The Recovery Partition is 300 MB The C partition is 1.72 TB, NTFS, 218 GB used, 1.51 TB free The destination drive is 1.81 TB, NTFS, 678 GB used, 1.15 TB free I've fiddled with vssadmin resize shadowstorage, with no change in the error. vssadmin list shadowstorage displays: Shadow Copy Storage association For volume: (C:)\?\Volume{37a0...263}\ Shadow Copy Storage volume: (C:)\?\Volume{37a0...263}\ Used Shadow Copy Storage space: 2.39 GB (0%) Allocated Shadow Copy Storage space: 2.81 GB (0%) Maximum Shadow Copy Storage space: 531 GB (30%) Shadow Copy Storage association For volume: (F:)\?\Volume{2a2...94f}\ Shadow Copy Storage volume: (F:)\?\Volume{2a2...94f}\ Used Shadow Copy Storage space: 334 GB (17%) Allocated Shadow Copy Storage space: 337 GB (18%) Maximum Shadow Copy Storage space: UNBOUNDED (922154758%) (Yeah, the "percent calculation" for UNBOUNDED is seriously bogus.) I've run SFC /verifyonly and it seems happy. I've verified that the new `Volume Shadow Copy" service starts when I start the backup operation. Any suggestions?

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  • Using Javascript to call the Azure Blob Storage REST API

    - by user350829
    I'm developing a Flash app that saves files to the Azure Blob Storage API. I've learned that you should use the REST API directly rather than a go-between WCF service as this is the most efficient (using a web role is a bottleneck). The problem is that Flash can't do PUT or DELETE methods over Http and has to use external Javascript. This is not an area that I'm familiar with and need some advice/links to examples of using Javascript to work with the Storage API (I've obviously Googled this to no avail). Is this even possible? The Javascript would be hosted in a web role on the same domain. Many thanks, Ed

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  • Azure storage: Uploaded files with size zero bytes

    - by Fabio Milheiro
    When I upload an image file to a blob, the image is uploaded apparently successfully (no errors). When I go to cloud storage studio, the file is there, but with a size of 0 (zero) bytes. The following is the code that I am using: // These two methods belong to the ContentService class used to upload // files in the storage. public void SetContent(HttpPostedFileBase file, string filename, bool overwrite) { CloudBlobContainer blobContainer = GetContainer(); var blob = blobContainer.GetBlobReference(filename); if (file != null) { blob.Properties.ContentType = file.ContentType; blob.UploadFromStream(file.InputStream); } else { blob.Properties.ContentType = "application/octet-stream"; blob.UploadByteArray(new byte[1]); } } public string UploadFile(HttpPostedFileBase file, string uploadPath) { if (file.ContentLength == 0) { return null; } string filename; int indexBar = file.FileName.LastIndexOf('\\'); if (indexBar > -1) { filename = DateTime.UtcNow.Ticks + file.FileName.Substring(indexBar + 1); } else { filename = DateTime.UtcNow.Ticks + file.FileName; } ContentService.Instance.SetContent(file, Helper.CombinePath(uploadPath, filename), true); return filename; } // The above code is called by this code. HttpPostedFileBase newFile = Request.Files["newFile"] as HttpPostedFileBase; ContentService service = new ContentService(); blog.Image = service.UploadFile(newFile, string.Format("{0}{1}", Constants.Paths.BlogImages, blog.RowKey)); Before the image file is uploaded to the storage, the Property InputStream from the HttpPostedFileBase appears to be fine (the size of the of image corresponds to what is expected! And no exceptions are thrown). And the really strange thing is that this works perfectly in other cases (uploading Power Points or even other images from the Worker role). The code that calls the SetContent method seems to be exactly the same and file seems to be correct since a new file with zero bytes is created at the correct location. Does any one have any suggestion please? I debugged this code dozens of times and I cannot see the problem. Any suggestions are welcome! Thanks

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  • Silverlight isolated storage: what identifies an "application"?

    - by Joe White
    The docs for Silverlight's IsolatedStorageFile.GetUserStoreForApplication just say that the isolated storage is specific to the "application", and that each different application will have its own storage independent of all other "applications" (but with one quota for the entire domain). That's great, but I haven't found anything yet that explains just what "application" is supposed to mean (either in the Silverlight docs or the regular .NET Framework docs). What information does Silverlight, in particular, use to decide that "this is application A" and "this is application B"? Does it just go off the URI to the .xap file, or what?

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  • Access block level storage via kernel

    - by N 1.1
    How to access block level storage via the kernel (w/o using scsi libraries)? My intent is to implement a block level storage protocol over network for learning purpose, almost the same way SCSI works. Requests will be generated by initiator and sent to target (both userspace program) which makes call to kernel module and returns the data using TCP protocol to initiator. So far, I have managed to build a simple "Hello" module and run it (I am new at kernel programming), but unable to proceed with block access. After searching a lot, I found struct buffer_head * bread(int dev,int block) in linux/fs.h, but the compiler throws error. error: implicit declaration of function ‘bread’ Please help, also feel free to advice on starting with kernel programming. Thank you!

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  • Storage for large gridded datasets

    - by nullglob
    I am looking for a good storage format for large, gridded datasets. The application is meteorology, and we would prefer a format that is common within this field (to help exchange data with others). I don't need to deal with special data structures, and there should be a Fortran API. I am currently considering HDF5, GRIB2 and NetCDF4. How do these formats compare in terms of data compression? What are their main limitations? How steep is the learning curve? Are there any other storage formats worth investigating? I have not found a great deal of material outlining the differences and pros/cons of these formats (there is one relevant SO thread, and a presentation comparing GRIB and NetCDF).

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  • Are there any home/soho NAS devices that will backup/sync to the cloud?

    - by 3rdparty
    Looking for a home office (SOHO) market (priced) network hard drive (NAS) that will sync some or all of its content to a cloud-based backup service. The only option I've been able to find so far is NetGear's [ReadyNAS Vault][1] however from what I've read it's not as secure as it could be, and the service is quite expensive ($200/yr for 50GB of cloud storage) - it's 'powered' by ElephantDrive Ideally would love to see something like Wuala integrated into a Lacie Network HDD - conveniently, I suspect this is in the works as Lacie recently acquired Wuala, however nothing has come of it yet. I know there are options to use rsync with a customizable NAS (such as the very versatile and hackable D-Link DNS-323, but the easier this is to setup and maintain, the better. Thanks! ps. I had many links posted within this question, but was limited to posting with only one due to anti-spam restrictions - gotta get my 'reputation' higher!

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  • MySQL unstable behavior with external stroge

    - by onurozcelik
    In our project we are using MySQL 5.0.90(InnoDB engine) server with an external storage. We store MySQL data files in an external storage. When the external storage down for a reason we have unstable behaviours. So we made some tests. In Windows Server 2008 We closed external storage physically. MySQL service stoped and we could not reach the server. Then we opened the storage unit and we could not start service until we reconfigured MySQL. We made storage unit offline from operating system. After 3-4 minutes and some insert trials(some insert trials succeded) MySQL service stoped and we could not reach the server. Then we made storage unit online and we could start the service(not automatically). In Windows Server 2003 We made storage unit offline. After 3-4 minutes and some insert trials(some insert trials succeded) MySQL service stoped and we could not reach the server. Then we made storage unit online we could not start the service until we reinstalled MySQL. Before reinstall we tried to reconfigure but it did not work. We closed external storage physically. MySQL service stoped and we could not reach the server. After that we opened the storage unit and we could start service(not automatically) We expect service to autostart after storage unit is online/open. But these tests show unstable behaviors. Is there any solutions to this.

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  • Flexible cloud file storage for a web.py app?

    - by benwad
    I'm creating a web app using web.py (although I may later rewrite it for Tornado) which involves a lot of file manipulation. One example, the app will have a git-style 'commit' operation, in which some files are sent to the server and placed in a new folder along with the unchanged files from the last version. This will involve copying the old folder to the new folder, replacing/adding/deleting the files in the commit to the new folder, then deleting all unchanged files in the old folder (as they are now in the new folder). I've decided on Heroku for the app hosting environment, and I am currently looking at cloud storage options that are built with these kinds of operations in mind. I was thinking of Amazon S3, however I'm not sure if that lets you carry out these kinds of file operations in-place. I was thinking I may have to load these files into the server's RAM and then re-insert them into the bucket, costing me a fortune. I was also thinking of Progstr Filer (http://filer.progstr.com/index.html) but that seems to only integrate with Rails apps. Can anyone help with this? Basically I want file operations to be as cheap as possible.

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  • XenServer 5.5 local storage problem

    - by Jason Nerer
    Hi community, I have the following problem with a Citrix XenServer 5.5. I had to physically move the host, so I shut down all machines via console: xe vm-shutdown force=true vm=my-machine-uuis-s After that I shut down the machine itself by issuing: halt After the reboot today the local storage repository is unplugged. I was trying to repair it via XenCenter, but I don't trust this one. So I tried: [root@xenserver ~]# xe pbd-list uuid ( RO) : ef6e2f3b-5825-393c-23e1-391d105c87ec host-uuid ( RO): c4bcf09c-2e52-448f-8210-df5d13bd33a9 sr-uuid ( RO): 2fb3be9c-075c-53ed-acb6-42f0c4ad0614 device-config (MRO): device: /dev/disk/by-id/scsi-SATA_WDC_WD5001ABYS-_WD-WCAS83698154,/dev/disk/by-id/scsi-SATA_WDC_WD5001ABYS-_WD-WCAS83694262 currently-attached ( RO): false To reattach the storage I issued: xe pbd-plug uuid=ef6e2f3b-5825-393c-23e1-391d105c87ec That one is running now for a while but not talking to me. The local repo has around 1TB. Should I wait, or are there any other options to reattach the local repo? What could have caused this problem? Any ideas? Thx. J

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  • Large scale storage for incrementally-appended documents?

    - by Ben Dilts
    I need to store hundreds of thousands (right now, potentially many millions) of documents that start out empty and are appended to frequently, but never updated otherwise or deleted. These documents are not interrelated in any way, and just need to be accessed by some unique ID. Read accesses are some subset of the document, which almost always starts midway through at some indexed location (e.g. "document #4324319, save #53 to the end"). These documents start very small, at several KB. They typically reach a final size around 500KB, but many reach 10MB or more. I'm currently using MySQL (InnoDB) to store these documents. Each of the incremental saves is just dumped into one big table with the document ID it belongs to, so reading part of a document looks like "select * from saves where document_id=14 and save_id 53 order by save_id", then manually concatenating it all together in code. Ideally, I'd like the storage solution to be easily horizontally scalable, with redundancy across servers (e.g. each document stored on at least 3 nodes) with easy recovery of crashed servers. I've looked at CouchDB and MongoDB as possible replacements for MySQL, but I'm not sure that either of them make a whole lot of sense for this particular application, though I'm open to being convinced. Any input on a good storage solution?

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  • Temporary storage for keeping data between program iterations?

    - by mr.b
    I am working on an application that works like this: It fetches data from many sources, resulting in pool of about 500,000-1,500,000 records (depends on time/day) Data is parsed Part of data is processed in a way to compare it to pre-existing data (read from database), calculations are made, and stored in database. Resulting dataset that has to be stored in database is, however, much smaller in size (compared to original data set), and ranges from 5,000-50,000 records. This process almost always updates existing data, perhaps adds few more records. Then, data from step 2 should be kept somehow, somewhere, so that next time data is fetched, there is a data set which can be used to perform calculations, without touching pre-existing data in database. I should point out that this data can be lost, it's not irreplaceable (key information can be read from database if needed), but it would speed up the process next time. Application components can (and will be) run off different computers (in the same network), so storage has to be reachable from multiple hosts. I have considered using memcached, but I'm not quite sure should I do so, because one record is usually no smaller than 200 bytes, and if I have 1,500,000 records, I guess that it would amount to over 300 MB of memcached cache... But that doesn't seem scalable to me - what if data was 5x that amount? If it were to consume 1-2 GB of cache only to keep data in between iterations (which could easily happen)? So, the question is: which temporary storage mechanism would be most suitable for this kind of processing? I haven't considered using mysql temporary tables, as I'm not sure if they can persist between sessions, and be used by other hosts in network... Any other suggestion? Something I should consider?

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  • Sharing storage between servers

    - by El Yobo
    I have a PHP based web application which is currently only using one webserver but will shortly be scaling up to another. In most regards this is pretty straightforward, but the application also stores a lot of files on the filesystem. It seems that there are many approaches to sharing the files between the two servers, from the very simple to the reasonably complex. These are the options that I'm aware of Simple network storage NFS SMB/CIFS Clustered filesystems Lustre GFS/GFS2 GlusterFS Hadoop DFS MogileFS What I want is for a file uploaded via one webserver be immediately available if accessed through the other. The data is extremely important and absolutely cannot be lost, so whatever is implemented needs to a) never lose data and b) have very high availability (as good as, or better, than a local filesystem). It seems like the clustered filesystems will also provide faster data access than local storage (for large files) but that isn't of vita importance at the moment. What would you recommend? Do you have any suggestions to add or anything specifically to look out for with the above options? Any suggestions on how to manage backup of data on the clustered filesystems?

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  • High Performance Storage Systems for SQL Server

    Rod Colledge turns his pessimistic mindset to storage systems, and describes the best way to configure the storage systems of SQL Servers for both performance and reliability. Even Rod gets a glint in his eye when he then goes on to describe the dazzling speed of solid-state storage, though he is quick to identify the risks.

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  • Digital Storage for Airline Entertainment

    - by Bill Evjen
    by Thomas Coughlin Common flash memory cards The most common flash memory products currently in use are SD cards and derivative products (e.g. mini and micro-SD cards) Some compact flash used for professional applications (such as DSLR cameras) Evolution of leading flash formats Standardization –> market expansion Market expansion –> volume iNAND –> focus is on enabling embedded X3 iSSD –> ideal for thin form factor devices Flash memory applications Phones are the #1 user of flash memory Flash memory is used as embedded and removable storage in many mobile applications Flash memory is being used in computers as USB sticks and SSDs Possible use of flash memory in computer combined with HDDs (hybrid HDDs and paired or dual storage computers) It can be a removable card or an embedded card These devices can only handle a specific number of writes Flash memory reads considerably quicker than hard drives Hybrid and dual storage in computers SSDs can provide fast performance but they are expensive HDDs can provide cheap storage but they are relatively slow Combining some flash memory with a HDD can provide costs close to those of HDDs and performance close to flash memory Seagate Momentus XT hybrid HDD Various dual storage offerings putting flash memory with HDDs Other common flash memory devices USB sticks All forms and colors Used for moving files around Some sold with content on them (Sony Movies on USB sticks) Solid State Drives (SSDs) Floating Gate Flash Memory Cell When a bit is programmed, electrons are stored upon the floating gate This has the effect of offsetting the charge on the control gate of the transistor If there is no charge upon the floating gate, then the control gate’s charge determines whether or not a current flows through the channel A strong charge on the control gate assumes that no current flows. A weak charge will allow a strong current to flow through. Similar to HDDs, flash memory must provide: Bit error correction Bad block management NAND and NOR memories are treated differently when it comes to managing wear In many NOR-based systems no management is used at all, since the NOR is simply used to store code, and data is stored in other devices. In this case, it would take a near-infinite amount of time for wear to become an issue since the only time the chip would see an erase/write cycle is when the code in the system is being upgraded, which rarely if ever happens over the life of a typical system. NAND is usually found in very different application than is NOR Flash memory wears out This is expected to get worse over time Retention: Disappearing data Bits fade away Retention decreases with increasing read/writes Bits may change when adjacent bits are read Time and traffic are concerns Controllers typically groom read disturb errors Like DRAM refresh Increases erase/write frequency Application characteristics Music – reads high / writes very low Video – r high / writes very low Internet Cache – r high / writes low On airplanes Many consumers now have their own content viewing devices – do they need the airlines? Is there a way to offer more to consumers, especially with their own viewers Additional special content tie into airplane network access to electrical power, internet Should there be fixed embedded or removable storage for on-board airline entertainment? Is there a way to leverage personal and airline viewers and content in new and entertaining ways?

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  • Google I/O 2012 - Powering Your Application's Data using Google Cloud Storage

    Google I/O 2012 - Powering Your Application's Data using Google Cloud Storage Navneet Joneja, Nathan Herring Since opening its doors to all developers at Google I/O last year, the Google Cloud Storage team has shipped several features that let you use Google Cloud Storage for a variety of advanced use cases. This session will open with a quick introduction to the product, and quickly shift focus to implementing a variety of advanced applications using new features in Google Cloud Storage. For all I/O 2012 sessions, go to developers.google.com From: GoogleDevelopers Views: 48 1 ratings Time: 58:32 More in Science & Technology

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  • GDD-BR 2010 [2F] Storage, Bigquery and Prediction APIs

    GDD-BR 2010 [2F] Storage, Bigquery and Prediction APIs Speaker: Patrick Chanezon Track: Cloud Computing Time slot: F [15:30 - 16:15] Room: 2 Level: 101 Google is expanding our storage products by introducing Google Storage for Developers. It offers a RESTful API for storing and accessing data at Google. Developers can take advantage of the performance and reliability of Google's storage infrastructure, as well as the advanced security and sharing capabilities. We will demonstrate key functionality of the product as well as customer use cases. Google relies heavily on data analysis and has developed many tools to understand large datasets. Two of these tools are now available on a limited sign-up basis to developers: (1) BigQuery: interactive analysis of very large data sets and (2) Prediction API: make informed predictions from your data. We will demonstrate their use and give instructions on how to get access. From: GoogleDevelopers Views: 1 0 ratings Time: 39:27 More in Science & Technology

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  • How to fix Failed to initialize Windows Azure storage emulator error

    - by ybbest
    When you press F5 to start debugging Azure project, you might get the following exception: If you go to the Output windows, you will see the detailed error message below: Windows Azure Tools: Failed to initialize Windows Azure storage emulator. Unable to start Development Storage. Failed to start Development Storage: the SQL Server instance ‘localhost\SQLExpress’ could not be found. Please configure the SQL Server instance for Development Storage using the ‘DSInit’ utility in the Windows Azure SDK. This is because by default, Azure uses the SQLExpress to start Development Storage. To fix this you can do the following: You need to open command prompt, and navigate to C:\Program Files\Windows Azure SDK\v1.4\bin\devstore (depending on your Azure version, the file path is slightly different.) Next, run DSInit /sqlInstance:. (. Means the SQL Server use the default instance, if you have name instance, you need to change. to the name of the SQL Server) After a short while, you should see the following windows showing the configuration succeeds. You can download a batch file here. References: http://msdn.microsoft.com/en-us/library/gg433132.aspx

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