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.
236 Comments
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Hrel - Thursday, April 09, 2009 - link
Instead of making me dinner can you send me that test system instead??? Please!!! ReplyHrel - Thursday, April 09, 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. Replysfisher64 - Wednesday, April 08, 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? ReplyBaffo - 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. Replymarraco - Tuesday, April 07, 2009 - link
This article is popular :) ReplyBLHealthy4life - Monday, April 06, 2009 - link
Intel 9.1.1.1010 (Intel) Where are these drivers? I can only find version 1007 and not 1010....Thanks Reply
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 Reply
irondukes - Friday, April 03, 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 X25M Replymdavies - Friday, April 03, 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 Reply
sotoa - Friday, April 03, 2009 - link
Long time reader, first time post.I really liked the background story and appreciate how Anand delves deep into the the SSD's (as well as other products in other articles).
Thanks for looking out for the little guy!
Keep up the great work! Reply