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Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication
From: |
Troy Benjegerdes |
Subject: |
Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication |
Date: |
Wed, 2 Jan 2013 11:10:57 -0600 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
On Wed, Jan 02, 2013 at 05:16:03PM +0100, Beno??t Canet wrote:
> This patchset is a cleanup of the previous QCOW2 deduplication rfc.
>
> One can compile and install https://github.com/wernerd/Skein3Fish and use the
> --enable-skein-dedup configure option in order to use the faster skein HASH.
>
> Images must be created with "-o dedup=[skein|sha256]" in order to activate the
> deduplication in the image.
>
> Deduplication is now fast enough to be usable.
How does this code handle hash collisions, and do you have some regression
tests that purposefully create a dedup hash collision, and verify that the
'right thing' happens?
The next question is .. what's the right thing?
It's great that this almost works, but it seems rather dangerous to put
something like this into the mainline code without some regression tests.
(I'm also suspecting the regression test will be a great way to find
flakey hardware)
--------------------------------------------------------------------------
Troy Benjegerdes 'da hozer' address@hidden
Somone asked my why I work on this free (http://www.fsf.org/philosophy/)
software & hardware (http://q3u.be) stuff and not get a real job.
Charles Shultz had the best answer:
"Why do musicians compose symphonies and poets write poems? They do it
because life wouldn't have any meaning for them if they didn't. That's why
I draw cartoons. It's my life." -- Charles Shultz
- [Qemu-devel] [RFC V4 28/30] qcow: Set dedup cluster block size to 64KB., (continued)
- [Qemu-devel] [RFC V4 28/30] qcow: Set dedup cluster block size to 64KB., Benoît Canet, 2013/01/02
- [Qemu-devel] [RFC V4 27/30] qcow2: Use large L2 table for deduplication., Benoît Canet, 2013/01/02
- [Qemu-devel] [RFC V4 12/30] qcow2: Load and save deduplication table header extension., Benoît Canet, 2013/01/02
- [Qemu-devel] [RFC V4 16/30] qcow2: Extract qcow2_add_feature and qcow2_remove_feature., Benoît Canet, 2013/01/02
- [Qemu-devel] [RFC V4 06/30] qcow2: Add qcow2_dedup and related functions, Benoît Canet, 2013/01/02
- [Qemu-devel] [RFC V4 26/30] qcow2: Add lazy refcounts to deduplication to prevent qcow2_cache_set_dependency loops, Benoît Canet, 2013/01/02
- [Qemu-devel] [RFC V4 18/30] qcow2: Behave correctly when refcount reach 0 or 2^16., Benoît Canet, 2013/01/02
- [Qemu-devel] [RFC V4 11/30] qcow2: create function to load deduplication hashes at startup., Benoît Canet, 2013/01/02
- [Qemu-devel] [RFC V4 13/30] qcow2: Extract qcow2_do_table_init., Benoît Canet, 2013/01/02
- Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication,
Troy Benjegerdes <=
- Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication, Benoît Canet, 2013/01/02
- Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication, Troy Benjegerdes, 2013/01/02
- Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication, Benoît Canet, 2013/01/02
- Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication, ronnie sahlberg, 2013/01/02
- Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication, Benoît Canet, 2013/01/02
- Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication, Troy Benjegerdes, 2013/01/02
- Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication, ronnie sahlberg, 2013/01/02
- Re: [Qemu-devel] [RFC V4 00/30] QCOW2 deduplication, Stefan Hajnoczi, 2013/01/03