The SSD Anthology: Understanding SSDs and New Drives from OCZ
by Anand Lal Shimpi on March 18, 2009 12:00 AM EST- Posted in
- Storage
Simulating a Used Drive
Since SSD performance degrades over time, it’s important to not only look at how well these drives perform new - but also the worst they’d perform over their lifetime. In order to do so we’d need a repeatable way of “seasoning” a drive to reduce its performance to the worst it could possibly get. The most realistic worst-case scenario is one where every single block on the drive is full of data. If a secure erase wipes all LBAs, that’s the best place to start. To simulate a well seasoned drive I first secure erased the drive.
After the secure erase, I used iometer to write one contiguous file across the disk - filling up the entire drive with 128KB blocks. In the case of the 80GB Intel X25-M, that’s 74.5GB of data on the drive before I run a single benchmark. The spare area is left untouched.
Next, I take my test image and I restore it onto the partition with a sector by sector copy. The sequential file write made sure that data is stored in every page of the SSD, the test image restore adds a twist of randomness (and realism) to the data.
There are other ways to produce a drive in its well-used state, but this ends up being the most consistent and repeatable. To confirm that my little simulation does indeed produce a realistically worn drive I ran PCMark on three different drives: 1) a freshly secure-erased Intel X25-M, 2) an Intel X25-M setup using the method I just described and 3) the Intel X25-M used in my CPU testbed that has been through hundreds of SYSMark runs.
The benchmark of choice is PCMark Vantage; it simulates the real world better than most drive benchmarks. The results are below:
| Intel X25-M State | PCMark Vantage Overall Test | PCMark Vantage HDD Test |
| Fresh Secure Erase | 11902 | 29879 |
| Simulated Used Drive | 11536 | 23252 |
| Actual Testbed Used Drive | 11140 | 23438 |
The secure erased system loses about 3% of its overall performance and 22% of its hard drive specific performance compared to my testbed drive. The seasoning method I described above produces a drive with nearly identical drops in performance.
The method appears to be sound.
Now that we have a way of simulating a used drive, let’s see how the contestants fared.
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Hrel - Thursday, April 9, 2009 - link
although, I have some issues which I have put in an e-mail sent to Anand; can't wait for you response.Hrel - Thursday, April 9, 2009 - link
Instead of making me dinner can you send me that test system instead??? Please!!!Hrel - Thursday, April 9, 2009 - link
I was wondering what controller the OCZ solid Series is based on??? Will I experience hiccups with that drive or not? Is the point of my question.sfisher64 - Wednesday, April 8, 2009 - link
I just purchased a Dell Latitude E6400 with a 64GB Ultra Performance Solid State Drive. Does anyone know what type of drive this is, and where it fits in the spectrum described in this article?Baffo - Saturday, April 11, 2009 - link
The Dells use the Samsung drives (you should see this on the bottom if you pull it out). However, as much as I wish this was one of the newer controllers (I have a few of these at work as well), the testing cycles demanded by Dell probably mean these are the older controllers.marraco - Tuesday, April 7, 2009 - link
This article is popular :)BLHealthy4life - Monday, April 6, 2009 - link
Intel 9.1.1.1010 (Intel) Where are these drivers? I can only find version 1007 and not 1010....Thanks
BLHealthy4life - Sunday, April 12, 2009 - link
found it....Intel obviously keeps the X58 chipset drivers current for their own boards, just not other mfgs boards....
They installed fine on my R2E..
BL
irondukes - Friday, April 3, 2009 - link
Hi-- Do SLCs suffer from performance degradation, or are the controllers pretty agressive at erasing the data since they have far longer read-write cycles? Please help! Deciding between an X25E and X25Mmdavies - Friday, April 3, 2009 - link
I'm reading this about a day late - got my Patriot PE256GS25SSDR 2.5" 256GB yesterday since I'm bad about destroying hard drives. this drive, in a word, was excruciating. I'll be replacing it with one of your recommended drives today.Thanks