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I am using an Intel X25-E SSD for the system drive of a Windows Server 2008 R2 server with 16 GB RAM. Would it be good practice to move the pagefile to its own drive? If so, for the pagefile drive, would there be a preference for SSD or conventional hard drive?

The storage configuration also includes two data volumes, each of which is implemented on a 4-disk RAID 10 array, attached to a PERC 5/i Integrated RAID controller. The server is a Dell PowerEdge 2900. It has 10 slots in its backplane, one used for the SSD, eight used for the RAID 10 arrays, and one empty slot that is available for a pagefile drive.

Thanks.

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3 Answers

The traditional answer would be to separate the pagefile from the System drive but the X-25E's performance should generally make that unnecessary, especially on a server. If you can't put enough RAM in the system to avoid unnecessary paging, or you have applications (like Exchange 2007) that can make quite a lot of use of paging no matter what, then putting the page file on dedicated disks or on disks where the utilization is generally low remains a good idea.

However using a single X-25E for the system drive seems a bit strange to me. Whether it is a good idea or not to use SSD's for the system drive depends entirely on what you are using the server for but in most cases system drives on (properly configured) servers are not going to be the most significant IO bottleneck you want to control.

What I can say for certain though is that you should not use just one drive for system or normal data volumes. The standard practice of using two relatively small but reasonably fast drives (2x10K SAS) in RAID 1 provides sufficient performance to load the (mostly static) system drive files for most servers but guarantees you some level of failure resilience. SSD's might not be mechanical but they can, and do, still fail.

Ideally you want to use SSD's to eliminate something that is IOPS limited - your RAID 10 arrays are probably able to get close enough to matching the X-25E's transfer rate under most conditions but they wont come close to the IOPS (a couple of hundred at best versus many thousands for the X-25E). However since it's a single drive you should be very reluctant to put anything that you can't afford to lose completely on it - if it was me I'd be using it for temp file space (print spooling for example, scratch DB area for reporting etc).

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+1 Questioning the benefits of this particular configuration - the system disk on a server won't see much activity normally. –  Oskar Duveborn Aug 22 '09 at 21:43
    
This is a Terminal Server a/k/a Remote Desktop Session Host. –  sejong Aug 23 '09 at 1:12
    
The Users folder is redirected to one of the RAID 10 volumes during Windows Setup. My thinking about the one-disk system volume was that it can be restored from a bare-metal backup if necessary. –  sejong Aug 23 '09 at 5:22
    
Now your plan makes a lot more sense - you are likely to get a lot more utilization of a system drive for a Terminal Services server and a lot more paging than a typical server. I would still recommend two system disks though even if you have a very fast bare metal provisioning system. Given this clarification I think the best solution would be to get another X-25E and set that up with the first as RAID 1, then use that pack for System and paging. –  Helvick Aug 23 '09 at 10:32
    
Hardware RAID doesn't support TRIM so RAID in combination with SSDs at the moment is not a good idea. There isn't much of a performance impact of RAID 1 mirroring in software, so you can use that. –  JamesRyan Sep 22 '10 at 9:35
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Checkout http://blogs.msdn.com/e7/archive/2009/05/05/support-and-q-a-for-solid-state-drives-and.aspx

However, the below might apply more to consumer usage, than server usage, so take it with a grain of salt.


Should the pagefile be placed on SSDs?

Yes. Most pagefile operations are small random reads or larger sequential writes, both of which are types of operations that SSDs handle well.

In looking at telemetry data from thousands of traces and focusing on pagefile reads and writes, we find that

Pagefile.sys reads outnumber pagefile.sys writes by about 40 to 1,

Pagefile.sys read sizes are typically quite small, with 67% less than or equal to 4 KB, and 88% less than 16 KB.

Pagefile.sys writes are relatively large, with 62% greater than or equal to 128 KB and 45% being exactly 1 MB in size.

In fact, given typical pagefile reference patterns and the favorable performance characteristics SSDs have on those patterns, there are few files better than the pagefile to place on an SSD.

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Thanks for the link to the Windows Engineering Team blog. –  sejong Aug 24 '09 at 10:38
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I know that I'm going against popular opinion here, but I've run WinXP on several systems with no pagefile for years with no ill effects. I just bought an X-25 myself and installed XP with no page file. I just don't see the point in Window's archaic pagefile wearing out my SSD.

If XP will run fine with 1GB of RAM and a 1.5GB maximum pagefile, I don't see why it wouldn't run fine with 2.5GB of RAM and no pagefile. Under very rare conditions (like running photoshop with a ton of open windows and a lot of open Firefox windows and a few other memory hogs running) I get a low memory warning...but I'm pretty sure that's the same warning I would have gotten if my pagefile was maxing out. In any case, all I do is save my work and shut down some of the memory hogging applications and I'm fine.

//Rant on// Finally, if we "have to have pagefiles", I can't believe in 2009 we can't make a friggin RAM disk for the pagefile! I mean seriously, in 1986 on my Amiga I could create a fixed-size RAM drive that survived reboots (VD0: the ASDG recoverable RAM disk)! How can it be a quarter of the century later and we still don't have features we took for granted on the Amiga? //Rant off//

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I ran windows without pagesfiles for years, too, which lately has bitten me badly: I was editing a large picture in photoshop on my 8GB comp, and windows ran out of memory while editing. Well, I closed everything, tried to save the picture - problem was, photoshop needed more memory to save the picture, without pagefile there was no way to get more, so in the end I lost my editing on a very large picture, since the system could not give me any more memory. –  Sam Sep 1 '09 at 8:23
    
That's really painful. But the problem is that you ran out of memory. I'm sure that I could create the same conditions (with more or larger files) and create a crash even WITH a pagefile. And if you had more RAM, you wouldn't have crashed without a pagefile. Photoshop has its own temp/scratch directory as well. I wouldn't recommend disabling that...was it enabled on your system? –  Fred Hamilton Nov 28 '09 at 6:50
    
Pagefile on a ramdisk? Why not just get rid of that extra layer and just have more free ram?? –  surfasb Jul 21 '12 at 23:23
    
I totally agree in principle - was doing it with a RAM disk because A) I have a lot more RAM than 32bit WinXP can access, the ram disk goes in the extra RAM, so it's like free memory, and B) Some people seem to think (I don't think it's been proven one way or another) that Windows (or some Windows programs) is not happy unless there is a paging file. So this seemed like the best way to address that - the RAM disk is fast, has no impact on the RAM available to the OS, and the OS is happy because there's a paging file. –  Fred Hamilton Jul 22 '12 at 7:25
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