Does /proc/sys/vm/dirty_expire_centisecs influence the maximum time XFS
takes before the "in-memory but not on disk" preallocation actually
starts writing to disk? If not, which parameter does influence how long
files are grouped together in memory before writing them really to disk?
The longer the better for performance, but more risk for data loss of
I ask this because I want to know when copying files over the net to an
XFS drive, how I can prevent fragmentation to occur. Example: If a
packet of 1024 Bytes arrives every 1/100th second, it needs 0.64s to get
64KB of data, 1.28s to get 128KB. If the prealloc timeout is one second,
it's effectively not used in this case. So if you got a server where you
know files arrive at a certain speed, fine tuning this prealloc timeout
could help prevent fragmentation.
// Michael Monnerie, Ing.BSc ----- http://it-management.at
// Tel: 0660 / 415 65 31 .network.your.ideas.
// PGP Key: "curl -s http://zmi.at/zmi.asc | gpg --import"
// Fingerprint: AC19 F9D5 36ED CD8A EF38 500E CE14 91F7 1C12 09B4
// Keyserver: wwwkeys.eu.pgp.net Key-ID: 1C1209B4