System drive on SSD; pagefile to its own drive?
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.
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).
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.