[OpenIndiana-discuss] SSDs for OI hipster ZFS root mirror?
Bob Friesenhahn
bfriesen at simple.dallas.tx.us
Sat Aug 21 14:16:23 UTC 2021
The cost of atime is not very dramatic when using zfs except for
perhaps the snapshots issue which was already mentioned. This is
because the atime updates are cached in memory and are only written to
underlying store at the next zfs sync interval. So maybe atime will
be updated in the filesystem after 5 seconds, although a hundred
thousand or a million accesses occured in the mean time. It is pretty
common that when one file in a directory has been accessed, that many
files in that same directory have been accessed, so the number of
actual writes is reduced.
Support of atime from a network client is more serious since
supporting atime results in more network activity since the server
needs to be informed of it.
Regardless, I turn off atime support in all zfs filesystems and
network mounts where it is not needed.
It seems unlikely that atime is a serious factor when it comes to
concerns about wearing out a flash device unless it is an extremely
fragile device.
Bob
--
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
Public Key, http://www.simplesystems.org/users/bfriesen/public-key.txt
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