From 1b87f89b5c61f7b840663ddebaa58beb716bb1e9 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Wed, 4 Jul 2012 16:44:26 +0100 Subject: todo: Investigate qemu caching modes. --- TODO | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/TODO b/TODO index a89d52e7..247f98a1 100644 --- a/TODO +++ b/TODO @@ -498,3 +498,19 @@ should. There is a command line tool designed for scripts called this approach works, it doesn't solve the MBR problem, so likely we'd have to write a library for that (or perhaps go back to sfdisk but using a very abstracted interface over sfdisk). + +qemu caching +------------ + +(Suggested by Paolo Bonzini and Kevin Wolf) + +Measure the effect of cache=none, cache=directsync, +cache=writethrough, cache=writeback. + +It's doubtful that using cache=none is useful, since it disables the +host cache making read-heavy workloads slower (they rely entirely on +the smaller appliance kernel's cache). And in libguestfs we don't +necessarily care about ongoing data integrity while writing, as long +as data is reliably written out when g.sync or g.close return. Also +in libguestfs we effectively control the whole stack, so we can ensure +write barriers happen when we want. -- cgit