Re: TRIM support with XFS

On Sat, Jun 29, 2013 at 10:17 PM, Stan Hoeppner <stan@hardwarefreak.com> wrote:

Mount is miserly on the info it gives you. Post the output of
~$ cat /proc/mounts

rootfs / rootfs rw 0 0

sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0

proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0

udev /dev devtmpfs rw,relatime,size=10240k,nr_inodes=2043449,mode=755 0 0

devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0

tmpfs /run tmpfs rw,nosuid,noexec,relatime,size=1635204k,mode=755 0 0

/dev/disk/by-uuid/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx / xfs rw,noatime,attr2,delaylog,noquota 0 0

tmpfs /run/lock tmpfs rw,nosuid,nodev,noexec,relatime,size=5120k 0 0

tmpfs /run/shm tmpfs rw,nosuid,nodev,noexec,relatime,size=6601880k 0 0

/dev/sda1 /boot/efi vfat rw,relatime,fmask=0022,dmask=0022,codepage=cp437,iocharset=utf8,shortname=mixed,errors=remount-ro 0 0

rpc_pipefs /var/lib/nfs/rpc_pipefs rpc_pipefs rw,relatime 0 0

Doesn't look promising. The mount options in /etc/fstab is default,discard,native.

Then read this:
http://xfs.org/index.php/FITRIM/discard
and note [4]

/sys/block/sda/queue/discard_max_bytes says 2147450880. So it looks like at least the block device is recognized to support discard operations.

For a single user desktop productivity system, realtime discard w/XFS
probably won't show a noticeable negative impact, but this obviously
depends on your workloads. If you frequently delete very large files
(10s of GB), or very large numbers of files, then you may notice a slowdown.

Very infrequent. :-)

John