XFS and EXT4 Testing Concluded

I had a few more suggestions thrown out at me before I could wrap this one up.

  • Try disabling the RAID controller read-ahead
  • Try a few custom options to XFS
  • Try RAID-10

First, my final “best” state benchmarks for comparison:

FS  Raid Size Mount Options Transfer/s Requests/s Avg/Request 95%/Request
xfs 6 4T noatime,nodiratime,nobarrier 28.597Mb/sec 1830.24 0.51ms 2.06ms
ext4 6 4T noatime,nodiratime,nobarrier 32.583Mb/sec 2085.33 0.46ms 1.89ms

Disabling the read-ahead was an interesting thought.

FS RAID Size Mount Options Transfer/s Requests/s Avg/Request 95%/Request
xfs 6 4T noatime,nodiratime,nobarrier 28.704Mb/sec 1837.07 0.50ms 2.04ms
ext4 6 4T noatime,nodiratime,nobarrier 32.715Mb/sec 2093.75 0.46ms 1.88ms

It didn’t seem to make any real difference however.


The second suggestion was to use modified XFS options (mkfs.xfs -f -d sunit=128,swidth=$((512*8)),agcount=32 /dev/sdb2).

FS RAID Size Mount Options Transfer/s Requests/s Avg/Request 95%/Request
xfs 6 4T noatime,nodiratime,nobarrier 26.376Mb/sec 1688.07 0.55ms 2.18ms

It’s hard to tell, but it seems these actually degraded performance.


The last test was to switch to RAID-10. This would reduce overall storage capacity to 72TB, but given our requirements, this really shouldn’t cause any problem for the project. RAID-10 should have a significant boost to write performance.

FS RAID Size Mount Options Transfer/s Requests/s Avg/Request 95%/Request
xfs 10 36T noatime,nodiratime,nobarrier 32.808Mb/sec 2099.72 0.46ms 1.80ms
ext4 10 36T noatime,nodiratime,nobarrier 54.112Mb/sec 3463.17 0.28ms 1.11ms

These numbers back up the improvement to write speed, but XFS still lags behind at larger volume sizes.

Since I am had to reconfigure the array, I wanted to try the larger volume size (36T) above and then a smaller size (2T) to try to reproduce my earlier results showing XFS to perform better at lower volume size.

FS RAID Size Mount Options Transfer/s Requests/s Avg/Request 95%/Request
xfs 10 2.2T noatime,nodiratime,nobarrier 60.066Mb/sec 3844.2 0.25ms 1.00ms
ext4 10 2.2T noatime,nodiratime,nobarrier 64.766Mb/sec 4145.01 0.23ms 0.90ms

This was by far the best test results I had seen and has doubled the results from the original async test.


Testing conclusions

  • XFS seems to be very sensitive to partition size
  • In all but one case, EXT4 performed better on the random read-write tests
  • Know your other caveats of both file systems before picking the one for you
Advertisements

2 thoughts on “XFS and EXT4 Testing Concluded

  1. Pingback: XFS and EXT4 Testing Redux | MySQL and Stuff

  2. Pingback: XFS and EXT4 Testing Redux | InsideMySQL

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s