The SSD Relapse: Understanding and Choosing the Best SSD
by Anand Lal Shimpi on August 30, 2009 12:00 AM EST- Posted in
- Storage
The Wiper Tool
The only Microsoft OS with TRIM support is Windows 7. Windows XP and Vista users are out of luck when it comes to TRIM, even if your drive supports it, the OS will never send it the command. Luckily there’s a workaround, one first popularized by Indilinx - not Intel. Kudos to the Indilinx guys.
It’s called the Indilinx Wiper Tool.
The tool asks the OS for all available LBAs (free space as far as the OS is concerned), then feeds the list to the SSD and tells the drive to TRIM those LBAs - prioritizing them for cleaning. It shouldn’t touch valid data, the key word being shouldn’t. Once cleaned, with no existing data in those blocks, performance goes back to its new state.
It’s a very simple solution actually. TRIM works because the OS knows when a file is deleted and it uses the TRIM command to inform the SSD of the deletion. Don’t have OS level TRIM support? Well, just run a tool that asks the OS what locations aren’t in use any longer. You get the same result, it just takes one extra step: running the wiper tool.
See wiper.dat? It's eating up all available LBAs then telling the controller to TRIM those blocks. Clever.
I tested the Wiper Tool to make sure it worked as promised and indeed it did, I actually showed you the results at the beginning of this story. One pass of the tool and the drive went from used to new performance:
| PCMark Vantage HDD Score | New | "Used" | After TRIM/Idle GC | % of New Perf |
| OCZ Vertex Turbo (Indilinx MLC) | 26157 | 25035 | 26038 | 99.5% |
You’ll need to get the tool from your drive vendor and it currently works under both 32-bit and 64-bit Windows OSes (XP through 7). I found that it works best in IDE mode; with your controller set to RAID or AHCI I’ve seen issues where the manual trim process can easily take more than several hours. When running properly it takes a couple of minutes to trim an entire drive.
You don’t need to run the tool that often (Indilinx drives don’t drop significantly in real world performance anyway) and once we get official TRIM support, Windows 7 users won’t need to do anything at all. But until then it does provide a nice way to keep your drive fresh.
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zodiacfml - Wednesday, September 2, 2009 - link
Very informative, answered more than anything in my mind. Hope to see this again in the future with these drive capacities around $100.mgrmgr - Wednesday, September 2, 2009 - link
Any idea if the (mid-Sept release?) OCZ Colossus's internal RAID setup will handle the problem of RAID controllers not being able to pass Windows 7's TRIM command to the SSD array. I'm intent on getting a new Photoshop machine with two SSDs in Raid-0 as soon as Win7 releases, but the word here and elsewhere so far is that RAID will block the TRIM function.kunedog - Wednesday, September 2, 2009 - link
All the Gen2 X-25M 80GB drives are apparently gone from Newegg . . . so they've marked up the Gen1 drives to $360 (from $230):http://www.newegg.com/Product/Product.aspx?Item=N8...">http://www.newegg.com/Product/Product.aspx?Item=N8...
Unbelievable.
gfody - Wednesday, September 2, 2009 - link
What happened to the gen2 160gb on Newegg? For a month the ETA was 9/2 (today) and now it's as if they never had it in the first place. The product page has been removed.It's like Newegg are holding the gen2 drives hostage until we buy out their remaining stock of gen1 drives.
iwodo - Tuesday, September 1, 2009 - link
I think it acts as a good summary. However someone wrote last time about Intel drive handling Random Read / Write extremely poorly during Sequential Read / Write.Has Aanand investigate yet?
I am hoping next Gen Intel SSD coming in Q2 10 will bring some substantial improvement.
statik213 - Tuesday, September 1, 2009 - link
Does the RAID controller propagate TRIM commands to the SSD? Or will having RAID negate TRIM?justaviking - Tuesday, September 1, 2009 - link
Another great article, Anand! Thanks, and keep them coming.If this has already been discussed, I apologize. I'm still exhausted from reading the wonderful article, and have not read all 17 pages of comments.
On PAGE 3, it talks about the trade-off of larger vs. smaller pages.
I wonder if it would be feasible to make a hybrid drive, with a portion of the drive using small pages for faster performance when writing small files, and the majority of it being larger pages to keep the management of the drive reasonable.
Any file could be written anywhere, but the controller would bias small writes to the small pages, and large writes to large files.
Externally it would appear as a single drive, of course, but deep down in the internals, it would essentially be two drives. Each of the two portions would be tuned for maximum performance in different areas, but able to serve as backup or overflow if the other portion became full or ever got written to too many times.
Interesting concept? Or a hair brained idea buy an ignorant amateur?
CList - Tuesday, September 1, 2009 - link
Great article, wonderful to see insightful, in depth analysis.I'd be curious to hear anyone's thoughts on the implications are of running virtual hard disk files on SSD's. I do a lot of work these days on virtual machines, and I'd love to get them feeling more snappy - especially on my laptop which is limited to 4GB of ram.
For example;
What would the constant updates of those vmdk (or "vhd") files do to the disk's lifespan?
If the OS hosting the VM is windows 7, but the virtual machine is WinServer2003 will the TRIM command be used properly?
Cheers,
CList
pcfxer - Tuesday, September 1, 2009 - link
Great article!"It seems that building Pidgin is more CPU than IO bound.."
Obviously, Mr. Anand doesnt' understand how compilers work ;). Compilers will always be CPU and memory bound, reduce your memory in the computer to say 256MB (or lower) and you'll see what I mean. The levels of recursion necessary to follow the production (grammars that define the language) use up memory but would rarely use the drive unless the OS had terrible resource management. :0.
CMGuy - Wednesday, September 2, 2009 - link
While I can't comment on the specifics of software compilers I know that faster disk IO makes a big difference when your performing a full build (compilation and packaging) of software.IDEs these days spend a lot their time reading/writing small files (thats a lot of small, random, disk IO) and a good SSD can make a huge difference to this.