[lkml]   [2008]   [Jan]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [Patch] document ext3 requirements (was Re: [RFD] Incremental fsck)
> Writeback cache on disk in iteself is not bad, it only gets bad if the
> disk is not engineered to save all its dirty cache on power loss,
> using the disk motor as a generator or alternatively a small battery.
> It would be awfully nice to know which brands fail here, if any,
> because writeback cache is a big performance booster.

AFAIK no drive saves the cache. The worst case cache flush for drives is
several seconds with no retries and a couple of minutes if something
really bad happens.

This is why the kernel has some knowledge of barriers and uses them to
issue flushes when needed.

 \ /
  Last update: 2008-01-16 01:21    [W:0.295 / U:1.532 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site