qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [RFC V8 01/24] qcow2: Add journal specification.


From: Benoît Canet
Subject: Re: [Qemu-devel] [RFC V8 01/24] qcow2: Add journal specification.
Date: Wed, 3 Jul 2013 14:35:14 +0200
User-agent: Mutt/1.5.21 (2010-09-15)

> Does this mean the journal forms the first-stage data structure for
> deduplication?  Dedup records will accumulate in the journal until it
> becomes time to convert them in bulk into a more compact representation?

The journal is mainly used to persist the last inserted dedup metadata across
QEMU stop and restart. I replay it at startup to rebuild the hash table.
So yes it's the first stage even it's never used for regular queries.

> 
> When I read this specification I was thinking of a journal purely for
> logging operations.  You could use a commit record to mark previous
> records applied.  Upon startup, qcow2 would inspect uncommitted records
> and deal with them.

Maybe that could help regular QCOW2 usage. I don't know.



reply via email to

[Prev in Thread] Current Thread [Next in Thread]