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P128: Slow write after VBM19C1Q update and Secure Erase


Ben McCann

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I have a P128 (CORSAIR CMFSSD-128GBG2D) that still has slow write speeds (25 MB/sec) after upgrading to firmware VBM19C1Q and performing a Security Erase as documented at kernel.org.

 

For reference, I'm measuring write speeds on Linux so I don't have access to ATTO or other Windows based tools. I'm just using 'dd' to write 128KB blocks of zeros to a file hosted on a ext3 file system mounted '-o sync' to force Linux to write data synchronously (and not just to buffer cache):

 

dd if=/dev/zero of=test.dat bs=131072 count=200

200+0 records in

200+0 records out

26214400 bytes (26 MB) copied, 1.09126 s, 24.0 MB/s

 

The same test, writing to a pair of Western Digital Caviar Blacks in a Linux software RAID-1 array (using the 'md' driver) yields:

 

dd if=/dev/zero of=test.dat bs=131072 count=1000

1000+0 records in

1000+0 records out

131072000 bytes (131 MB) copied, 1.94738 s, 67.3 MB/s

 

I think this test, while basic, is a reasonable gage of the P128's performance. In fact, its generous because its issuing big (128KB) writes. A simple file copy of a 128 MB file onto the P128 is even slower. That runs at 7.8 MB/sec.

 

I purchased the drive in July 2009 and used it for about 6 months for heavy Linux based SW development. (A full compile and link would generate 10GB of object files). Its performance gradually degraded (no TRIM, Linux, etc) so I pulled it and went back to a regular drive.

 

I upgraded its firmware early this month (March 2010) and moved the drive into another PC to use as the OS and application SW drive but its write performance is still slow (as I reported above).

 

Is this drive worn out and should I return it under warranty? Is there any chance it suffers from slow writes because it uses Samsung Flash chips as documented by DailyTech? (For reference, its serial number is 09230615-8971104).

 

Is there anything else I can do to restore the write performance of this drive?

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Thanks, Yellowbeard.

 

The gparted directions include a step where you open a shell and run the 'hdparm' program to actually do the secure erase. (I.e. its not a feature built into gparted itself). Hdparm, freshly downloaded and built, was the same key step that I used.

 

I'm downloading partedmagic now to see if that works better.

 

Can you also answer one other question? Doesn't a firmware upgrade wipe the data on the drive? I wonder whether my upgrade to VBM19C1Q would have also 'secure erased' the drive.

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I'll check with the local expert, which I am not. But, I did sleep in a Holiday Inn Express last night. ::pirate::

 

All kidding aside, I have flashed a few of the Samsung based drives. The firmware update does "delete" the data but does not actually secure erase the drive aka write 0s to all of it. I had good luck with Parted Magic so far.

 

Let us know how it goes.

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The Update for the new Firmware takes less than a minute and to Secure erase would need more time than that. Once Firmware is updated best to run one of the programs listed above GParted, Parted Magic, or HDDErase to get the performance when first bought or close to it.
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The firmware update does "delete" the data but does not actually secure erase the drive aka write 0s to all of it.
Darn I thought upgrading firmware did restore the ssd's performance by itself. What's the best way to secure erase the drive with just a flash drive only?
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Good news, bad news...

 

I had to manually run the secure erase from a shell in PartedMagic because it insisted the drive was frozen. (I had to set a password on the drive as documented here. That finished in about 10 seconds, which was so fast that I was worried that it did not work.

 

However, a 'dd if=/dev/zero of=/dev/sdc bs=131072 count=1000' to the raw disk (which, in my system was /dev/sdc) yields a write speed of about 180 MB/sec. BE CAREFUL IF YOU REPEAT THIS YOURSELF BECAUSE YOUR SSD MAY BE SOME OTHER DRIVE.

 

So, MUCH BETTER write performance.

 

I then rebooted back to my normal Linux environment and laid out my partitions and created EXT4 (note, 4) file systems. I then repeated the same 'dd' command shown in my first posting. Same damn 25 MB/sec write speed. I repeated the 'dd' to a unformatted raw partition and I got 175 MB/sec!

 

So, my write performance problem yesterday was likely due to EXT4, and not the drive.

 

I have one partition that is still EXT3 and I tried 'dd' to that. That gets 57 MB/sec. That's not great but a lot better than 25. I need to do some research to see why EXT4 sucks so hard. If I find anything that materially helps EXT4 then I'll post it here.

 

EXT4 is the preferred choice for Linux on SSD because it supports TRIM...

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More good news...

 

If you mount an ext4 file system using the options 'noatime,barrier=0,data=writeback,nobh' as described here then the 'dd' performance test ('dd if=/dev/zero of=testfile.dat bs=131072 count=1000') improves from 25 MB/sec to 80 MB/sec. Much better!

 

Note that this test was performed with the filesystem also mounted with the sync option because I wanted to bypass the Linux buffer cache. Normally you would not use 'sync' and hence the actual performance in typical use would be even better.

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Darn I thought upgrading firmware did restore the ssd's performance by itself. What's the best way to secure erase the drive with just a flash drive only?

 

Mugen, keep an eye on the thread in our How To section regarding The Ultimate Bootable Flash Drive Tool.

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And I think you may be over thinking the problem, just let the system boot with the parted magic disk and the unplug the drive Power and Data then re-connect the drive run the erase and I would not suggest using exotic file systems with SSD drives unless they have been verified to work.
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I did unplug the SSD but the PartedMagic 'erase disk' utility still reported the drive was frozen. It was necessary to manually set a password and then run the secure erase using hdparm from the shell.

 

Ext4 is now the default file system type for Ubuntu Linux. I wouldn't consider it exotic. Its also the most mainstream file system on Linux that supports TRIM.

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