[mdlug] Some SSD notes

[Adam Tauno Williams]

On Thu, 2014-01-16 at 14:43 +0000, Ingles, Raymond wrote:
> 2.Add the 'noatime' and 'nodiratime' mount options to the root listing
> in /etc/fstab
> Unix filesystems typically keep track not just when a file was created
> or modified, but also when they are accessed. (Linus Torvalds has
> noted that causing a write operation for every read operation is
> pretty wonky...) Some software actually uses this (a few mail programs
> use it to check for unread mail, some backup tools, etc.) but mostly
> it's not that big a deal, and minimizing such writes can boost
> performance (and disk life) noticeably.

You can also mount without noatime / relatime and use "chattr +A
{target}" to disable a-time tracking on specific portions of your
hierarchy - like a source code repository, etc...  This is useful since
the cost of a-time tracking for most files is minimal as they are rarely
accessed;  using chattr you can just disable the tracking (a) where it
matters and (b) leaving the `default` behavior everywhere else.  A
significant advantage of chattr is that your preferences are recorded in
the file-system's meta-data and effective regardless of the mount
options used.

There was talk at one time of "relatime" becoming the *DEFAULT* for
ext4.  I don't know if/when that happened - but you might be using
"relatime" even without specifying it. <http://lwn.net/Articles/244384/>

You can also play with "commit=n" values to make I/O lazier.

-- 
Adam Tauno Williams <mailto:awilliam at whitemice.org> GPG D95ED383
Systems Administrator, Python Developer, LPI / NCLA