[Qemu-devel] (iSCSI-)Readcache in Qemu?

[Peter Lieven]

Hi,

is there any project or plans to integrate a readcache in qemu either for iscsi 
or for the whole block layer?

I was thinking of 2 options:
a) assign (up to) a fixed amount of ram for readcaching of a VMs disk I/O. 
Without SG_IO this seems
to be quite easy as there are only a handful of operations to intercept.
b) add SSDs to a Node and allow a VM to use up to X MB of that SSD as 
read-cache. This should still be
a benefit if the storage for the VMs is on a NAS.

I would like to do that independent of the OS for 2 reasons. First with iSCSI 
the OS
is not involved. And second I would like to be able to add a memory limit for 
the cache.

Peter