|
From: | Dor Laor |
Subject: | [Qemu-devel] Re: KVM call agenda for Apr 27 |
Date: | Tue, 27 Apr 2010 12:08:37 +0300 |
User-agent: | Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.0.4-1.fc12 Lightning/1.0b2pre Thunderbird/3.0.4 ThunderBrowse/3.2.8.1 |
On 04/27/2010 11:56 AM, Avi Kivity wrote:
On 04/27/2010 11:48 AM, Dor Laor wrote:Here's another option: an nbd-like protocol that remotes all BlockDriver operations except read and write over a unix domain socket. The open operation returns an fd (SCM_RIGHTS strikes again) that is used for read and write. This can be used to implement snapshots over LVM, for example.Why w/o read/writes?To avoid the copying.
Of course, just pass the offset+len on read/write too
the watermark code needs them too (as info, not the actual buffer).Yeah. It works for lvm snapshots, not for watermarks.IMHO the whole thing is way over engineered: a) Having another channel into qemu is complicating management software. Isn't the monitor should be the channel? Otherwise we'll need to create another QMP (or nbd like Avi suggest) for these actions. It's extra work for mgmt and they will have hard time to understand events interleaving of the various channelsblock layer plugins allow intercepting all interesting block layer events, not just write-past-a-watermark, and allow actions based on those events. It's a more general solution.
No problem there, as long as we do try to use the single existing QMP with the plugins. Otherwise we'll create QMP2 for the block events in a year from now.
b) How the plugins are defined? Is it scripts? Binaries? Do they open their own sockets?Shared objects.
[Prev in Thread] | Current Thread | [Next in Thread] |