SSDs and RAID-0 and sector size

[Slizzo]

Hey guys, my 2x Samsung 830s should be getting here sometime next week, and I plan on putting them in a RAID-0 array.

First question is what sector size should I pick for this type of setup?

Secondly, I know Intel was working on updating the RST driver to allow TRIM in RAID? I've heard some rumblings about a beta driver being out but nothing real concrete.

I will be turning off SRT of course, and will be using the 60GB Vertex2 as an additional drive to put games on, and the 300GB raptor will be a backup to that; the 1.5TB and 750GB drives will remain storage drives.


Any other tips would help, thanks!

Additional Comment:

So after doing some reading it looks like I want to align everything at 4k, that's simple enough.

As for the other question, anyone know if we have an available RST driver that supports TRIM on RAID arrays?

[Mr.Scott]

You don't have to align anything unless you plan on putting XP on them.

[itznfb]

When you build the array you want the largest cluster size possible. Mine is 128k. TRIM won't be supported on Windows 7. Windows 8 only.

[AruisDante]

Just use whatever default Windows picks for you. If you're installing 7 or 8 it's smart enough to know what an SSD is and automatically optimize the settings for it. As for actually selecting the RAID Stripe size, as itznfb said, just use the default which is 128k.

[OS-Wiz]

Well, cluster/strip size is NOT one size fits all. Picking the max size available does have an advantage, in most cases where fetch size is towards the larger sizes, of better read performance. Its downside is that it tends to waste space. This would be the case where most files are smaller than the stripe size, leaving small chunks of space in each segment unused and too small for future writes, and only a few larger.

The advantage of smaller stripe sizes is they use space better. The downside is slower read performance for larger fetches.

When you are constrained to a single RAID array, as most home users are, stripe size should be picked based on the average fetch size of the most important and heavily used files on your system.

In large commercial file servers we employ several RAID arrays of varying stripe sizes to match the varying fetch sizes. E.g. smaller stripe sizes for OLTP workloads and much larger stripe sizes for data warehouse workloads.

[PommieB]

Trim only working on raid0 in win8 is a rumor, there is no evidence to support it at all, the new rst driver released a few weeks ago, doesn't seem to support trim in raid0 either, I've failed to find concrete evidence that trim supports raid 0 at this point. Early days yet.

Apparently not working in either win7 or win8 with the latest rst driver, some say it does, tests say it doesn't. Not sure about the win8 rumor, there's a lot of speculation, it would suck if that's the case.

[AruisDante]

Originally Posted by OS-Wiz

Well, cluster/strip size is NOT one size fits all. Picking the max size available does have an advantage, in most cases where fetch size is towards the larger sizes, of better read performance. Its downside is that it tends to waste space. This would be the case where most files are smaller than the stripe size, leaving small chunks of space in each segment unused and too small for future writes, and only a few larger.

The advantage of smaller stripe sizes is they use space better. The downside is slower read performance for larger fetches.

When you are constrained to a single RAID array, as most home users are, stripe size should be picked based on the average fetch size of the most important and heavily used files on your system.

In large commercial file servers we employ several RAID arrays of varying stripe sizes to match the varying fetch sizes. E.g. smaller stripe sizes for OLTP workloads and much larger stripe sizes for data warehouse workloads.

Ha ha I think that kind of optimization is a bit much for the average home user. But yes, obviously there are situations where smaller is better. Just not in most home desktop ones

[Slizzo]

This is the quick guide I found that had a lot of good information in it on Windows 7 and SSDs.

http://www.overclock.net/t/1156654/s...-for-ssds-hdds

[PommieB]

Actually as very little info on ssd's, but as excellent info on win7, checked it out months ago, these guy's here have posted more info on ssd's.

[AruisDante]

Originally Posted by PommieB

Actually as very little info on ssd's, but as excellent info on win7, checked it out months ago, these guy's here have posted more info on ssd's.

In addition most of that stuff is done automatically on Windows 7 with SP1 or later.

[OS-Wiz]

Originally Posted by AruisDante

Ha ha I think that kind of optimization is a bit much for the average home user. But yes, obviously there are situations where smaller is better. Just not in most home desktop ones

Well, for the average home user with expensive SSDs trying to get the most value from it, using the NTFS default block size of 8K for clustersize might be a good trade-off between performance and space utilization.