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  • Is it okay to resend to hard bounced emails after X days. What is X?

    - by V. Hsu
    If I see an email returned due to a hard bounce, after how many days is it acceptable to resend to that email address. It is possible for emails to be reactivated or for temporary outages, so it doesn't make sense to keep an email in my hard bounce email list forever. I've already seen cases where I receive emails from addresses that were put in my hard bounce email list months ago. Any recommendations? Are there specific recommendations from ISPs?

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  • Strange loss of format on pen drive

    - by Kiewic
    Hi, here is an screenshot of my pen drive. The files are impossible to open, and the names have been replaced by strange characters. In Ubuntu is worst, the Windows system crash. What can I do to recover my information?

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  • How can I access my external hard drive wirelessly from my laptop?

    - by leora
    My desktop crashed so I am migrated over to a laptop. I have wireless in my home so i am trying to be able to use to laptop in any room without any other connections (wireless printer, wireless mouse, etc) The one issue i have is that my desktop had 2 external hard drives (USB) connected to them and i am trying to figure out the best way to treat these as external drives without having to plug them into the laptop directly. My external hard drive is the Western Digital WDH1U5000N 500GB and my laptop is a Dell D620.

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  • Why will multiple dvd/cd-rom drives stop reading?

    - by ddc0660
    I'm having difficulty with two dvd/cd drives. When I updated from XP to Vista, I noticed they wouldn't work. I could add cds or dvds to the drives and they would attempt to read the disk, but never "found" a disk in the drive. Vista showed the drives existed without problems. I updated their drivers and nothing changed. I thought perhaps, oddly, both drives were going bad. Then I got Windows 7, and I figured I'd have to do some gymnastics in order to get it onto my system without a working disk drive. However, I can boot from the Windows 7 disk fine! I installed 7 hoping that it was a Vista problem and I'd reclaim my drives, but that is not the case. The same symptoms persist. Thoughts?

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  • Windows 7 not detecting external hard drive but Ubuntu is detecting. Why?

    - by unlimit
    I have a 500 GB Toshiba external hard drive. Since yesterday Windows 7 stopped detecting it, however I do see it listed on the "Safely remove hardware and eject media" icon on the taskbar. Then I tried the same external hard drive on my Ubuntu and it detected it just fine. Ubuntu and Windows 7 are on the same laptop. I have dual boot. Can someone tell me why is it happening? Am I missing a driver in Windows 7? Additional info: This drive has worked perfectly fine in the past. I did not format this drive ever. It just stopped working yesterday in windows.

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  • How do I get back hard drive space after I have uninstalled Ubuntu from Windows?

    - by Shantanu
    I installed Ubuntu on windows like it says to do it on Ubuntu's website as an application. I did not want it to create a separate partition on my hard drive. A few days ago, I uninstalled Ubuntu by going into the Windows control panel and hitting uninstall. As you would expect, I would get back my 100 or so gb on the disc. i never really installed anything of importance on ubuntu so i never had a second thought about uninstalling it. But I never got back my 100gb from Ubuntu. Now when I add up all of the folders on my c drive, they total to the amount I had on windows before I uninstalled Ubuntu but when I look at the My Computer screen, it says that another 100 or so gb is missing. I tried defragmenting the disc, downloading various disc managers but nothing fixed the space problem. Can anyone please help me with this!!??? Any help is much appreciated! Just making sure: UBUNTU WAS NOT ON A SEPARATE PARTITION, IT WAS INSTALLED AS AN APPLICATION ON WINDOWS. It tells yuo how to do this here except i did it with a much older version (i think it was 8.04 or soemthing): http://www.ubuntu.com/download/help/install-ubuntu-with-windows

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  • SQL Server: avoiding hard coding of database name in cross-database views

    - by codeulike
    So, lets say you have two SQL Server Databases on the same server that reference each others tables in their Views, Functions and Stored Procedures. You know, things like this: use database_foo create view spaghetti as select f.col1, c.col2 from fusilli f inner join database_bar.dbo.conchigli c on f.id = c.id (I know that cross-database views are not very good practice, but lets just say you're stuck with it) Are there any good techniques to avoid 'hard coding' the database names? (So that should you need to occasionally re-point to a different database - for testing perhaps - you don't need to edit loads of views, fns, sps) I'm interested in SQL 2005 or SQL 2008 solutions. Cheers.

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  • eventmachine and external scripts via backticks

    - by Maciek
    I have a small HTTP server script I've written using eventmachine which needs to call external scripts/commands and does so via backticks (``). When serving up requests which don't run backticked code, everything is fine, however, as soon as my EM code executes any backticked external script, it stops serving requests and stops executing in general. I noticed eventmachine seems to be sensitive to sub-processes and/or threads, and appears to have the popen method for this purpose, but EM's source warns that this method doesn't work under Windows. Many of the machines running this script are running Windows, so I can't use popen. Am I out of luck here? Is there a safe way to run an external command from an eventmachine script under Windows? Is there any way I could fire off some commands to be run externally without blocking EM's execution? edit: the culprit that seems to be screwing up EM the most is my usage of the Windows start command, as in: start java myclass. The reason I'm using start is because I want those external scripts to start running and keep running after the EM request is served

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  • Turn A Flash Drive Into a Portable Web Server

    - by Matthew Guay
    Portable applications are very useful for getting work done on the go, but how about portable servers?  Here’s how you can turn your flash drive into a portable web server. Getting Started To put a full web server on our flash drive, we’re going to use XAMPP Lite.  This lightweight, preconfigured server includes recent versions of Apache, MySQL, and PHP so you can run most websites and webapps directly from it.  You could use the full XAMPP, which includes more features such as a FileZilla FTP server and OpenSSL, but for most purposes, the light version is plenty for a portable server. Download the latest version of XAMPP Lite (link below).  In this tutorial, we used the self-extracting EXE version; you could choose the ZIP file and extract the files yourself, but we found it easier to use the executable. Run the installer, and click Browse choose where to install your server. Select your flash drive, or a folder in it, and click Ok.  Make sure your flash drive has at least 250MB of available storage space.  XAMPP will create an xampplite folder and store all the files in it during the installation.   Click Install, and all of the files will be extracted to your flash drive.  This may take a few moments depending on your flash drive’s speed. When the extraction process is finished, a Command Prompt window will open to finish the installation.  The first prompt will ask if you want to add shortcuts to the start menu and desktop; enter “n” since we don’t want to create start menu links to our portable server. Now enter “y” to configure XAMPP’s directories automatically. Finally, enter “y” to make XAMPP fully portable.  It will set up the servers to run without specific drive letters so your server will run from any computer. XAMPP will finalize your changes; press Enter when everything is completed. Setup will automatically launch the command line version of XAMPP.  On first run, confirm that your time zone is correct. And that’s it!  You can now run XAMPP’s control panel by entering 1, or you can exit and run XAMPP from any other computer with your flash drive. To complete your portable webserver kit, you may want to install Portable Firefox or Iron Browser on your flash drive so you always have your favorite browser ready to use. Running your portable server Using your portable server is very simple.  Open the xampplite folder on your flash drive and launch xampp-control.exe. Click Start beside Apache and MySql to get your webserver running. Please note: Do not check the Svc box, as this will run the server as a Windows service.  To keep XAMPP portable, you do not want it running as a service! Windows Firewall may prompt you that it blocked the server; click Allow access to let your server run. Once they’re running, you can click Admin to open the default XAMPP admin page running from your local webserver.  Or, you can view it by browsing to http://localhost/ or http://127.0.0.1/ in your browser. If everything is working correctly, you should see this page in your browser.  Choose your default language… And then you’ll see the default XAMPP admin page.   Click the Status link on the left sidebar to make sure everything is running correctly. If you click the Admin button for MySql in the XAMPP Control Panel, it will open phpMyAdmin in your default browser.  Alternately, you can open the MySql admin page by entering http://localhost/phpmyadmin/ or http://127.0.0.1/phpmyadmin/ in your favorite browser. Now you can add your own webpages to your webserver.  Save all of your web files in the \xampplight\htdocs\ folder on your flash drive. Install WordPress in your portable server Since XAMPP Lite includes MySql and PHP, you can even run webapps such as WordPress, the popular CMS and blogging platform.  Download WordPress (link below), and extract the files to the \xampplite\htdocs folder on your flash drive. Now all of the WordPress files are stored in \xampplite\htdocs\wordpress on your flash drive. We still need to setup WordPress on our portable server.  Open your MySql admin page http://localhost/phpmyadmin/ to create a new database for WordPress.  Enter a name for your database in the “Create new database” box, and click Create. Click the Privileges tab on the top, and the select “Add a new User”.   Enter a username and password for the database, and then click the Go button on the bottom of the page. Using WordPress Now, in your browser, enter http://localhost/wordpress/wp-admin/install.php.  Click Create a Configuration File to continue. Make sure you have your Database name, username, and password we created previously, and click “Let’s Go!” Enter your WordPress database name, username, and password, leave the other two entries as default, and click Submit. You should now have the database all ready to go.  Click “Run the install” to finish installing WordPress. Enter a title, username, and password for your test blog, as well as your email address, and then click “Install WordPress”. You now have a portable install of WordPress.  Click “Log In” to  access your WordPress admin page. Enter your username and password, and click Log In. Here you can add pages, posts, themes, extensions, and anything else just like you would on a normal WordPress site.  This is a great way to experiment with WordPress without messing up your real website. You can view your portable WordPress site by entering http://localhost/wordpress/ in your address bar. Closing your server When you’re done running your test server, click the Stop button on each of the services and then click the Exit button in the XAMPP control panel.  If you press the exit button on the top of the window, it will just minimize the control panel to the tray.   Alternately, you can shutdown your server by running xampp_stop.exe from your xampplite folder. Conclusion XAMPP Lite gives you a great way to run a full webserver directly from your flash drive.  Now, anywhere you go, you can test and tweak your webpages and webapps from any Windows computer.  Links Download XAMPP Lite Download WordPress Similar Articles Productive Geek Tips BitLocker To Go Encrypts Portable Flash Drives in Windows 7How To Use BitLocker on Drives without TPMSpeed up Your Windows Vista Computer with ReadyBoostView and Manage Flash Cookies the Easy WayInstall and Run Applications from Your iPod, Flash Drive or Mp3 Player 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 OutlookStatView Scans and Displays General Usage Statistics How to Add Exceptions to the Windows Firewall Office 2010 reviewed in depth by Ed Bott FoxClocks adds World Times in your Statusbar (Firefox) Have Fun Editing Photo Editing with Citrify Outlook Connector Upgrade Error

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  • Access Home Network Server via External Address (DSL vs Cable)

    - by Dominic Barnes
    For the last few months, I've been using a server on my home network for basic backups and hosting some small websites. Up until this past week, I've been using Comcast (cable) as an ISP and now that I've moved into an apartment, I'm using AT&T. (DSL) I've set up dynamic DNS and I can verify it works externally. However, I can't seem to access the public address from within the local network. Is there something DSL does differently from Cable that makes this frustration possible?

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  • Access Home Network Server via External Address (DSL vs Cable)

    - by Dominic Barnes
    For the last few months, I've been using a server on my home network for basic backups and hosting some small websites. Up until this past week, I've been using Comcast (cable) as an ISP and now that I've moved into an apartment, I'm using AT&T. (DSL) I've set up dynamic DNS and I can verify it works externally. However, I can't seem to access the public address from within the local network. Is there something DSL does differently from Cable that makes this frustration possible?

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  • DVD-RW Drive not recognizing a DVD+R disc

    - by unknown (yahoo)
    Hi everyone, I am having trouble burning DVD+R disc's. My OS is vista and i have used this burner and these same discs in the past. I haven't had the need to do so in months and now that i come back to create some backups my DVD/RW drive doesn't recognize a brand new DVD+R disc. These disc are the same ones i have used in the past(Same Pack even). Anyone have any idea what this might be. Maybe a vista upgrade or something that i downloaded in the last few months that could have thrown something off? Thanks in advance.

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  • mac: How to mount ejected external hdd again

    - by Maurice Kroon
    I've used my WD My Book 1TB for quite some time now. I always simply unplug it without officially 'ejecting' it. However, yesterday I did eject it (the partitions) before unplugging it. However, now, when i reconnect the hdd, it does not show the drives. It only shows the WD SmartWare partition (which is empty btw). The rest doesn't start. Does anyone know how to mount an unmounted disk? thx in advance!

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  • 6 Ways to Free Up Hard Drive Space Used by Windows System Files

    - by Chris Hoffman
    We’ve previously covered the standard ways to free up space on Windows. But if you have a small solid-state drive and really want more hard space, there are geekier ways to reclaim hard drive space. Not all of these tips are recommended — in fact, if you have more than enough hard drive space, following these tips may actually be a bad idea. There’s a tradeoff to changing all of these settings. Erase Windows Update Uninstall Files Windows allows you to uninstall patches you install from Windows Update. This is helpful if an update ever causes a problem — but how often do you need to uninstall an update, anyway? And will you really ever need to uninstall updates you’ve installed several years ago? These uninstall files are probably just wasting space on your hard drive. A recent update released for Windows 7 allows you to erase Windows Update files from the Windows Disk Cleanup tool. Open Disk Cleanup, click Clean up system files, check the Windows Update Cleanup option, and click OK. If you don’t see this option, run Windows Update and install the available updates. Remove the Recovery Partition Windows computers generally come with recovery partitions that allow you to reset your computer back to its factory default state without juggling discs. The recovery partition allows you to reinstall Windows or use the Refresh and Reset your PC features. These partitions take up a lot of space as they need to contain a complete system image. On Microsoft’s Surface Pro, the recovery partition takes up about 8-10 GB. On other computers, it may be even larger as it needs to contain all the bloatware the manufacturer included. Windows 8 makes it easy to copy the recovery partition to removable media and remove it from your hard drive. If you do this, you’ll need to insert the removable media whenever you want to refresh or reset your PC. On older Windows 7 computers, you could delete the recovery partition using a partition manager — but ensure you have recovery media ready if you ever need to install Windows. If you prefer to install Windows from scratch instead of using your manufacturer’s recovery partition, you can just insert a standard Window disc if you ever want to reinstall Windows. Disable the Hibernation File Windows creates a hidden hibernation file at C:\hiberfil.sys. Whenever you hibernate the computer, Windows saves the contents of your RAM to the hibernation file and shuts down the computer. When it boots up again, it reads the contents of the file into memory and restores your computer to the state it was in. As this file needs to contain much of the contents of your RAM, it’s 75% of the size of your installed RAM. If you have 12 GB of memory, that means this file takes about 9 GB of space. On a laptop, you probably don’t want to disable hibernation. However, if you have a desktop with a small solid-state drive, you may want to disable hibernation to recover the space. When you disable hibernation, Windows will delete the hibernation file. You can’t move this file off the system drive, as it needs to be on C:\ so Windows can read it at boot. Note that this file and the paging file are marked as “protected operating system files” and aren’t visible by default. Shrink the Paging File The Windows paging file, also known as the page file, is a file Windows uses if your computer’s available RAM ever fills up. Windows will then “page out” data to disk, ensuring there’s always available memory for applications — even if there isn’t enough physical RAM. The paging file is located at C:\pagefile.sys by default. You can shrink it or disable it if you’re really crunched for space, but we don’t recommend disabling it as that can cause problems if your computer ever needs some paging space. On our computer with 12 GB of RAM, the paging file takes up 12 GB of hard drive space by default. If you have a lot of RAM, you can certainly decrease the size — we’d probably be fine with 2 GB or even less. However, this depends on the programs you use and how much memory they require. The paging file can also be moved to another drive — for example, you could move it from a small SSD to a slower, larger hard drive. It will be slower if Windows ever needs to use the paging file, but it won’t use important SSD space. Configure System Restore Windows seems to use about 10 GB of hard drive space for “System Protection” by default. This space is used for System Restore snapshots, allowing you to restore previous versions of system files if you ever run into a system problem. If you need to free up space, you could reduce the amount of space allocated to system restore or even disable it entirely. Of course, if you disable it entirely, you’ll be unable to use system restore if you ever need it. You’d have to reinstall Windows, perform a Refresh or Reset, or fix any problems manually. Tweak Your Windows Installer Disc Want to really start stripping down Windows, ripping out components that are installed by default? You can do this with a tool designed for modifying Windows installer discs, such as WinReducer for Windows 8 or RT Se7en Lite for Windows 7. These tools allow you to create a customized installation disc, slipstreaming in updates and configuring default options. You can also use them to remove components from the Windows disc, shrinking the size of the resulting Windows installation. This isn’t recommended as you could cause problems with your Windows installation by removing important features. But it’s certainly an option if you want to make Windows as tiny as possible. Most Windows users can benefit from removing Windows Update uninstallation files, so it’s good to see that Microsoft finally gave Windows 7 users the ability to quickly and easily erase these files. However, if you have more than enough hard drive space, you should probably leave well enough alone and let Windows manage the rest of these settings on its own. Image Credit: Yutaka Tsutano on Flickr     

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  • Access Home Network Server via External Address

    - by Dominic Barnes
    For the last few months, I've been using a server on my home network for basic backups and hosting some small websites. Up until this past week, I've been using Comcast (cable) as an ISP and now that I've moved into an apartment, I'm using AT&T. (DSL) I've set up dynamic DNS and I can verify it works externally. However, I can't seem to access the public address from within the local network. Is there something DSL does differently from Cable that makes this frustration possible?

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  • jump to page of a pdf in google docs / drive / apps

    - by Aaron - Solution Evangelist
    i want to jump to a specific page of a pdf file via the google docs via the editor url https://docs.google.com/file/d/xxx/edit or the embed url https://docs.google.com/file/d/xxx/preview i am not looking to use the http://docs.google.com/gview?url= referenced in the stackoverflow question how to open specific page on Google's docs viewer as i want to do this for documents where authentication is required the the document is not available via public url. is there some way of appending an anchor (i would have expected it to be https://docs.google.com/file/d/xxx/preview#10) or a query (e.g. https://docs.google.com/file/d/xxx/preview?page=10) to the google docs / drive / apps viewer?

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  • My EliteBook is not auto picking 1080p for external monitor, poor display on forcing

    - by Griever
    I'm connecting my Samsung LED S22A300B to my HP EliteBook 6930p through VGA out. Laptop has Intel 4500MHD video card. I have latest drivers installed for both card and monitor. Only 800x600 and 1024x768 are shown. A lot of other people get this problem when they use it with docking station as discussed here. But I am not using any docking station. The monitor works great with my desktop though. As advised on the aforementioned page, one of the things I tried was to force the resolution using Intel's "custom resolution" feature. I installed PowerStrip on my desktop and copied advanced timing values(front/back porch,sync width, etc.) from there and then used the same values while defining a custom resolution in my laptop's Intel graphics utility. As a result, I got the 1080p resolution but the display is poor. Text has some weird colored shadow and sometimes on images too. What should I do?

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  • 59 vs 60 hertz on external display via DisplayPort

    - by Shiki
    Don't know if this is a really specific question or you'll help me out. Please do. I just bought a DeLock DisplayPort cable for my Lenovo T500. Tried to use it with the in-built Intel MHD4500, no use. With the ATI HD3650 (you can switch between the two vga on this machine) I get a normal picture, but only on 59hz. On 60 I get a smaller desktop size (strange). Any idea what can cause this? Will I have any problem if I use the 59hz? (Was using the display with a VGA cable but I get a blurry picture with that (dont matter what device I attach, VGA is like this on this display) and thats why I wanted to change.)

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  • User's home drive permissions don't contain system or administrators on Windows Server 2008 R2

    - by JohnyV
    I have a user whose home drive has only that user in the permissions. No administrators, etc. I have tried to take ownership as a local administrator however I cant seem to apply settings to the child objects -- it still gives me a permission denied error. I know there are some handy CLI utils that can redo permissions. Any ideas? Or even a way to do it through Windows? The file server is a 2008 R2 server.

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  • Windows XP loses drive letter for existing partition on disk

    - by Kev
    Hi, apologies if this has already been asked - I couldn't spot anything exactly the same. I'm looking for help on the fact that Windows XP has suddenly decided to stop assigning a drive letter to the second partition on my laptop's disk. I haven't added or changed hardware and I keep everything pretty clean in terms of software installed. I've partitioned the disk into a system partition on C: and a user partition on d: but lately, when booting or coming out of hibernation or sometime from stand-by, Windows will lose it's d: mapping. If I notice and remap it from MMC, everything will be perfectly happy and will keep going. Any help on this will be greatly appreciated. Cheers, Kev

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  • Powershell and long-running external tools?

    - by leeand00
    I'm trying to compact a MS-Access database using JetComp.exe using a powershell script. Here is the operative lines: # 4. Run JetComp LogWrite("Begin: Running JetComp") .\JETCOMP.EXE -src: $srcDB -dest: $dstDB | Out-Null #Run this command and wait for it to finish... IfErrorExit("Error Compacting Database") LogWrite("End: Running JetComp") The JETCOMP.EXE program seems to complete long before it is actually finished and the $dstDB ends up being smaller than the compact should even make it. Initially ($srcDB) it's about 1.8 GB and by the time the command finishes it's about 300,000 kb (about 0.29 gb) that's a pretty long way off from 1.8 gb which when compacted manually ends up being about 1.6 gb. Is there some sort of timeout I don't know about in powershell scripts? P.S. I know that when running JETCOMP.EXE manually, that the system often detects it as "not responding" even though it's actually getting the job done, and waiting long enough will allow it to complete.

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  • External Hardrive Not Reconized on Windows 7 at all

    - by Bella
    I Have a NextStar 2/5" from Vantec and its an 80G HD. I have used it many times on windows xp and it works fine. We just recently upgraded to windows 7 home premium and when I plug it in it beeps many times. I've tried all the USB plugs in my computer and its not those plugs. Haven't tried eSata because it uses a weird cable to plug into. People told me that when it beeps everything is corrupted, but works fine on xp. I tried installing the drivers online from their website and when I try it asks me to put in a cd which makes no sense because they are online drivers. When I go into device manager nothing comes up, it just acts like the HD is invisible. The beeping will stop eventually as it is plugged in, but with no result.

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  • Cost Comparison Hard Disk Drive to Solid State Drive on Price per Gigabyte - dispelling a myth!

    - by tonyrogerson
    It is often said that Hard Disk Drive storage is significantly cheaper per GiByte than Solid State Devices – this is wholly inaccurate within the database space. People need to look at the cost of the complete solution and not just a single component part in isolation to what is really required to meet the business requirement. Buying a single Hitachi Ultrastar 600GB 3.5” SAS 15Krpm hard disk drive will cost approximately £239.60 (http://scan.co.uk, 22nd March 2012) compared to an OCZ 600GB Z-Drive R4 CM84 PCIe costing £2,316.54 (http://scan.co.uk, 22nd March 2012); I’ve not included FusionIO ioDrive because there is no public pricing available for it – something I never understand and personally when companies do this I immediately think what are they hiding, luckily in FusionIO’s case the product is proven though is expensive compared to OCZ enterprise offerings. On the face of it the single 15Krpm hard disk has a price per GB of £0.39, the SSD £3.86; this is what you will see in the press and this is what sales people will use in comparing the two technologies – do not be fooled by this bullshit people! What is the requirement? The requirement is the database will have a static size of 400GB kept static through archiving so growth and trim will balance the database size, the client requires resilience, there will be several hundred call centre staff querying the database where queries will read a small amount of data but there will be no hot spot in the data so the randomness will come across the entire 400GB of the database, estimates predict that the IOps required will be approximately 4,000IOps at peak times, because it’s a call centre system the IO latency is important and must remain below 5ms per IO. The balance between read and write is 70% read, 30% write. The requirement is now defined and we have three of the most important pieces of the puzzle – space required, estimated IOps and maximum latency per IO. Something to consider with regard SQL Server; write activity requires synchronous IO to the storage media specifically the transaction log; that means the write thread will wait until the IO is completed and hardened off until the thread can continue execution, the requirement has stated that 30% of the system activity will be write so we can expect a high amount of synchronous activity. The hardware solution needs to be defined; two possible solutions: hard disk or solid state based; the real question now is how many hard disks are required to achieve the IO throughput, the latency and resilience, ditto for the solid state. Hard Drive solution On a test on an HP DL380, P410i controller using IOMeter against a single 15Krpm 146GB SAS drive, the throughput given on a transfer size of 8KiB against a 40GiB file on a freshly formatted disk where the partition is the only partition on the disk thus the 40GiB file is on the outer edge of the drive so more sectors can be read before head movement is required: For 100% sequential IO at a queue depth of 16 with 8 worker threads 43,537 IOps at an average latency of 2.93ms (340 MiB/s), for 100% random IO at the same queue depth and worker threads 3,733 IOps at an average latency of 34.06ms (34 MiB/s). The same test was done on the same disk but the test file was 130GiB: For 100% sequential IO at a queue depth of 16 with 8 worker threads 43,537 IOps at an average latency of 2.93ms (340 MiB/s), for 100% random IO at the same queue depth and worker threads 528 IOps at an average latency of 217.49ms (4 MiB/s). From the result it is clear random performance gets worse as the disk fills up – I’m currently writing an article on short stroking which will cover this in detail. Given the work load is random in nature looking at the random performance of the single drive when only 40 GiB of the 146 GB is used gives near the IOps required but the latency is way out. Luckily I have tested 6 x 15Krpm 146GB SAS 15Krpm drives in a RAID 0 using the same test methodology, for the same test above on a 130 GiB for each drive added the performance boost is near linear, for each drive added throughput goes up by 5 MiB/sec, IOps by 700 IOps and latency reducing nearly 50% per drive added (172 ms, 94 ms, 65 ms, 47 ms, 37 ms, 30 ms). This is because the same 130GiB is spread out more as you add drives 130 / 1, 130 / 2, 130 / 3 etc. so implicit short stroking is occurring because there is less file on each drive so less head movement required. The best latency is still 30 ms but we have the IOps required now, but that’s on a 130GiB file and not the 400GiB we need. Some reality check here: a) the drive randomness is more likely to be 50/50 and not a full 100% but the above has highlighted the effect randomness has on the drive and the more a drive fills with data the worse the effect. For argument sake let us assume that for the given workload we need 8 disks to do the job, for resilience reasons we will need 16 because we need to RAID 1+0 them in order to get the throughput and the resilience, RAID 5 would degrade performance. Cost for hard drives: 16 x £239.60 = £3,833.60 For the hard drives we will need disk controllers and a separate external disk array because the likelihood is that the server itself won’t take the drives, a quick spec off DELL for a PowerVault MD1220 which gives the dual pathing with 16 disks 146GB 15Krpm 2.5” disks is priced at £7,438.00, note its probably more once we had two controller cards to sit in the server in, racking etc. Minimum cost taking the DELL quote as an example is therefore: {Cost of Hardware} / {Storage Required} £7,438.60 / 400 = £18.595 per GB £18.59 per GiB is a far cry from the £0.39 we had been told by the salesman and the myth. Yes, the storage array is composed of 16 x 146 disks in RAID 10 (therefore 8 usable) giving an effective usable storage availability of 1168GB but the actual storage requirement is only 400 and the extra disks have had to be purchased to get the  IOps up. Solid State Drive solution A single card significantly exceeds the IOps and latency required, for resilience two will be required. ( £2,316.54 * 2 ) / 400 = £11.58 per GB With the SSD solution only two PCIe sockets are required, no external disk units, no additional controllers, no redundant controllers etc. Conclusion I hope by showing you an example that the myth that hard disk drives are cheaper per GiB than Solid State has now been dispelled - £11.58 per GB for SSD compared to £18.59 for Hard Disk. I’ve not even touched on the running costs, compare the costs of running 18 hard disks, that’s a lot of heat and power compared to two PCIe cards!Just a quick note: I've left a fair amount of information out due to this being a blog! If in doubt, email me :)I'll also deal with the myth that SSD's wear out at a later date as well - that's just way over done still, yes, 5 years ago, but now - no.

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