Optimising the Performance of Your SSD Disk

First, find out if your drive supports the TRIM extension:

# hdparm -I /dev/sda1 | grep TRIM
   *    Data Set Management TRIM supported (limit 8 blocks)
   *    Deterministic read data after TRIM

Then, make sure you're using ext4 or btfs file system and the following parameters to your/etc/hosts for your SSD disks:

# vi /etc/fstab

My old configuration looked like this. This is the default set up if you run through the Debian installer (2012-08-09 09:45, for readability, I've replaced the UUID with the actual disk drive, for you it might be some UUID gibberish like: UUID=89ee37b9-c00e-445e-9350-0e1e5f124275)

/dev/sda1 / ext4 errors=remount-ro 0 1

Then, add thediscard and noatime parameters:

/dev/sda1 / ext4 errors=remount-ro,discard,noatime 0 1

Thediscard parameter should make use of the TRIM extension and ensure that your SSD disk performs (almost) equally well when it gets older as it did when it was new.

Thenoatime is a safe performance parameter regardless of SSD or not, you might have read about it before, it's been there for a long time and works on other file systems too, likeext3

Finally, remount your partition (there's no need to reboot it):

# mount -o remount /dev/sda1

You should now see increased hard disk performance, especially as the SSD drive gets older (thediscard should work wonders here). You can test the hard drive performance by runninghdparm multiple times with and without the parameters set:

# for i in {0..5}; do hdparm -Tt /dev/sda1 ; done

My machines

As a reference and yard stick(s), you can have a look at the number of some of my machines:

128GB Crucial m4 2.5-inch SATA 6Gb/s (Model number: M4-CT128M4SSD2)

Mount options:

$ mount | grep " on / " | cut -d' ' -f3-
/ type ext4 (rw,relatime,errors=remount-ro,user_xattr,commit=600,barrier=1,data=ordered,discard)


# for i in {0..5}; do hdparm -Tt /dev/sda1 ; done
Timing cached reads:   14160 MB in  2.00 seconds = 7085.00 MB/sec
Timing buffered disk reads: 1214 MB in  3.00 seconds = 404.49 MB/sec

Timing cached reads:   14092 MB in  2.00 seconds = 7051.14 MB/sec
Timing buffered disk reads: 1216 MB in  3.00 seconds = 405.29 MB/sec

Timing cached reads:   14238 MB in  2.00 seconds = 7123.76 MB/sec
Timing buffered disk reads: 1212 MB in  3.00 seconds = 403.98 MB/sec

Timing cached reads:   12386 MB in  2.00 seconds = 6196.75 MB/sec
Timing buffered disk reads: 1214 MB in  3.01 seconds = 403.99 MB/sec

Timing cached reads:   13762 MB in  2.00 seconds = 6885.45 MB/sec
Timing buffered disk reads: 1216 MB in  3.00 seconds = 405.21 MB/sec

Timing cached reads:   13576 MB in  2.00 seconds = 6792.06 MB/sec
Timing buffered disk reads: 1210 MB in  3.00 seconds = 403.02 MB/sec

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