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.
Facebook
Twitter
RSS
250 Comments
View All Comments
Natfly - Wednesday, March 18, 2009 - link
DangerMouse4269 - Tuesday, April 13, 2010 - link
Nicely written. Even a very out of practice Comp Eng understood that.geekforhire - Monday, June 14, 2010 - link
I have just replaced the hard drive in this 3 year old Dell Inspiron 9400 notebook computer with a new and very quick OCZ SSD, manually configured the partition with a 1024 offset, freshly installed the OS, freshly downloaded all of the latest and greatest drivers from Dell, and applied all currently available OS updates from Msft.The problem is that when the machine resumes from Standby, it will /reliably/ (4 out of 4 attempts) produce a BSOD 0xF4 after the power button is pressed to resume the machine from standby.
Here's the sequence to recreate the problem:
0) Machine is booted normally into Windows, and log in to an account which has administrative privs.
1) Click on Start -> Shut Down -> Standby.
2) See display turn black, disk I/O light flashes then stops, then the power indicator light begins to flash on and off slowly.
3) Wait until the power light has made 2 slow flashes.
4) Press the power button.
5) See the Dell Bios splash screen, then disappear
6) Boom: See the BSOD 0xF4
The values reported after the STOP are:
(0x00000003, 0x865b3020, 0x865b3194, 0x805d2954)
Note that I've been in contact with OCZ before about this SSD+computer, because the previous BSOD that was produced was 0x77. Their recommendation was to create the partition with an offset with a 64 interval, and to reflash the SSD with their modern firmware. This was done, the OS was reinstalled as described, and now I'm getting a different BSOD code. Another mention was a question whether the notebook computer uses a SATA2 controller (definitely compatible) or SATA1 (which may have troubles).
I've run Spinrite on the SSD, and there are lots of ECC errors being reported. I've been in contact with Spinrite, and they chalk this up to the SSD being chatty (which they like), but since SSD's are new and magnetic disks are common, they want to stay focussed on magnetic disks.
When the machine boots back up, the OS reports that a serious error has occurred, and asks that a problem report be submitted, which I do. Then an attractive but somewhat generic page is displayed with common causes (Aging or failing hard disks, large file transfers from secondary media to local hd, loss of power to a hard drive, hard disk intensive processes (eg: antivirus scanners), recently installed hardware that might have compatibility and performance problems)
Has anyone else encountered this kind of problem, and do you have any suggestions?
angavar - Thursday, September 9, 2010 - link
As a medical student I can appreciate a well researched and analytical article when I see it. This is by far the best computer hardware review I have ever read! Thank-you for your time and effort in producing what is clearly a thoroughly researched and detailed analysis.mac021 - Wednesday, October 17, 2012 - link
Thank you for the lesson and helping me understand SSD drives. May I just ask for your advice...For everyday use designing and generating prototypes for websites and running typical office s/w like word and excel for long documentations while listening to music or just having some video play in the background, then the occasional gaming of, say Star Craft 2 and Dead Space 3, and lets assume I do this on a 5 hours a day average for 365 days in a year, how long before I need to replace an OCZ Vertex/Summit SSD? And does format/reinstall help in prolonging the life of an SSD just as it does for my old hard drives (from a computer that's 6 years old and counting)? Or there's no stopping the SSD's death after reaching 10,000 times of being erased and rewritten on? I'm not one who keeps upgrading or buying new computer systems for every new thing that comes out, i'm more of a keeper and maintainer for as long as the system servers my needs... but when I make a purchase, I make sure it will be enough to last me another 6-12 years IF possible! Which is why I'm still considering SATA for my next purchase late this year or early next year (and I'm only buying a new PC just because I made a mistake buying a foxconn motherboard that can't support anything higher than XP, not even Vista... weird, anyway I found that out too late).
Also, would you know of a motherboard that supports SSD, Windows 8, Nvidea, third gen i5/i7, and up to 64GB ram?
Thanks so much!
windows10 - Wednesday, November 30, 2016 - link
This article is meaningfull, interesting. thank you for sharingsusanbones - Tuesday, September 12, 2017 - link
I was wondered to these many responses here.