10-18-2011 09:50 PM
I have two 64 GB M4 drives in a RAID0 array. This is installed under Windows XP Pro SP3 on an Asus P5Q Deluxe, using the first two ICH10R SATA-2 ports on the system. When I first installed the M4s, five weeks ago, performance was fine. Below is an AS SSD run taken shortly after install.
Now, however, performance has diminised, and the write performance iw very poor. Below is the current AS SSD report.
When I look at device properties for the array, I see that the write cache is enabled.
Can anyone suggest why the performace is so much worse? or what I might try? Thanks.
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10-18-2011 10:04 PM - edited 10-18-2011 10:08 PM
images are moderated, so it may be a few before we see them. what intel rst management/driver are you using?
when you say 'device properties', do you mean windows, or the intel rst application advanced settings (again,i can't see your images yet)?
10-19-2011 02:43 PM
I have checked to ensure that the cache is enabled . I looked in both the Windows System Device Manager and in the Intel Rapid Storage Technology application. Both show that write caching is enabled.
The intel RST version is 18.104.22.1684. But the version is not really my question. The M4 drives were fast with this version, but now they are slow.
I have just finised imaging my system, then doing a secure erase of the M4s, and then restoring the image to the freshly-erased drives. I ran AS SDD against this clean set of drives, and the performance is still very poor -- essentially the same as my earlier post.
Just for clarity, in case the images do not show up, these are what I see.
When first installed Five weeks later
Read Write Read Write
Seq 505.42 205.57 507.76 206.02
4K 23.96 120.41 21.11 15.98
4K-64Thrd 275.31 181.94 158.01 17.83
The 4K write tests are one-eighth what they were, and the 64K read is only 3/5 what it was.
What's going on? Thanks.
10-19-2011 04:37 PM - edited 10-19-2011 04:41 PM
use the latest version of rst. those are ancent drivers/app. it still looks like no write back, as those low numbers are the exact numbers that benefit from the intel/windows caching. i would do a fresh install after secure erasing them. i would also, once you have updated your intel drivers, turned on intel write back caching, then go to the windows caching option, and uncheck it, reboot, then re check it. sometimes the windows cache option will show checked, but in fact it's not active.
if it's not the caching, you must be writing a bunch to them constantly, without letting the drives GC kick in.
edit: i notice you have the array now labeled E:
what are you using the array for now?
10-19-2011 08:11 PM
The drive has seven partitions on it (three primary and four logical). The E partition is 50GB with roughly 35GB free, and so seemed a to be the nicest idlest place to run the test. I did a trial on the C partition and it showed the same slow rate as the E.
I am leery of trying a new Intel RST on my Windows XP Pro. Every time I go to the Intel site and search, it tells me that I have the current version for XP Pro. Once not long ago I went ahead and installed RST 10.6.0.1022, following advice on a different manufacturer's forum. Within one day this version killed one, and possibly two, 60GB SSDs from that manufacturer (they were a Sandforce variant); both went back for RMA. It was to replace these that I bought the Crucial M4 drives.
You advise "reinstall". I have at least 350 programs installed, many heavily customized, plus much history, and reinstall is not a reasonable option. I am just swapping one disk drive, a standard SATA interface disk drive, for another, and that should not require a reinstall.
I will experiment with the cache-enable checking stuff again. And again, the drives were fast with my current drivers and hardware, and then slowed down. Note that the latest tests were done immediately after a secure erase (and image restore), which should obviate the garbage-collection effect.
Do you know of any way to tell for sure whether the drives are caching?
10-19-2011 09:33 PM - edited 10-19-2011 09:44 PM
these are not sandforce drives. out of curiosity, why so many partitions? benching will use whatever free nand is available, so os partitions mean nothing to the controller/bench in this regard, only physical drives.
10-19-2011 10:07 PM - edited 10-19-2011 10:32 PM
your partiton alignment is off. that's why you are getting these results.
for optimal results, all of your partitions may need to be redone to bring into spec re ssd requirements.
edit: we have been seeing as ssd, as of late, showing mis aligned partitons as ok. for a safe bet, atm, i'd try the anvils storage utilities bench:
10-20-2011 10:13 AM
My partitions are aligned properly to the best of my ability to verify this: (a) AS SDD reports them as aliogned; (b) Anvil Benchmark reports them as aligned; (c) arithmetic done on the starting absolute sector number reveals that they are aligned. For example of (c), the E-partition begins on sector 73,472,000 (decimal) according to Acronis Disk Director. 73472000 divided by 2048 (2048 sectors of 512 bytes equals one megabyte binary) equals 35875 exactly -- and the partition is aligned exactly on a binary megabyte boundary. This is true of all the partitions, and it is I believe the requirement for alignment for performance on SSDs.
I have now installed the Intel Rapid Storage Technology Driver version 10.6.0.1022, which is the latest, and find no difference in performance. The 4K and 64-thread 4K rates are still in the 17MB area. I did the disable-cache and reboot the enable-cache and reboot exercises with no change. (The Windows Hardware Device Manager policy status regarding cache and the Intel RST application status regarding cache mirror each other -- change one, and the change is instantaneously reflected in the other. For all this work I used the Intel RST application to make changes.)
But there is something puzzling with these latest drivers. With the RST application you can click on the icon for the RAID array to get its status and also on the icons for the individual disks comprising the array to get their staus. No matter what I pick for the RAID array cache status -- "write back cache" enable or disable -- the disks themselves show that the "disk data cache"is disabled. And there is no way to change this disk-drive-level staus that I can find.
So possibly the RAID array is operating with a windows-software-level buffer for a cache but with no caching in the drive-level hardware. If so, how do I enable it? Any ideas?
10-20-2011 10:28 AM
I found a program, dskcache.exe, that is part of Windows, and it is able to enable the drive-level cache. Again, this makes no performance differene. Intel reports that the array is cache-enabled and that the individual drives are cache-enabled, but still I am getting 17MB or so on the two M4s. It sure was nice when they were giving me 180 or so. What can have happened? I really am not writing that much data, and the secure erase (partedmagic method) should have wiped out the garbage anyway.