From: Stefan Hajnoczi <stefanha@redhat.com>
To: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Cc: kwolf@redhat.com, qemu-devel@nongnu.org, pbonzini@redhat.com,
den@openvz.org, jsnow@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2 RFC 0/8] block: persistent dirty bitmaps
Date: Thu, 11 Jun 2015 21:06:32 +0100 [thread overview]
Message-ID: <20150611200632.GA29013@stefanha-thinkpad.redhat.com> (raw)
In-Reply-To: <1433776886-27239-1-git-send-email-vsementsov@virtuozzo.com>
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The load/store API is not scalable when bitmaps are 1 MB or larger.
For example, a 500 GB disk image with 64 KB granularity requires a 1 MB
bitmap. If a guest has several disk images of this size, then multiple
megabytes must be read to start the guest and written out to shut down
the guest.
By comparison, the L1 table for the 500 GB disk image is less than 8 KB.
I think something like qcow2-cache.c or metabitmaps should be used to
lazily read/write persistent bitmaps. That way only small portions need
to be read/written at a time.
Stefan
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next prev parent reply other threads:[~2015-06-11 20:06 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-08 15:21 [Qemu-devel] [PATCH v2 RFC 0/8] block: persistent dirty bitmaps Vladimir Sementsov-Ogievskiy
2015-06-08 15:21 ` [Qemu-devel] [PATCH 1/8] spec: add qcow2-dirty-bitmaps specification Vladimir Sementsov-Ogievskiy
2015-06-09 16:01 ` John Snow
2015-06-09 17:03 ` Stefan Hajnoczi
2015-06-10 8:19 ` Vladimir Sementsov-Ogievskiy
2015-06-10 8:49 ` Vladimir Sementsov-Ogievskiy
2015-06-10 13:00 ` Eric Blake
2015-06-11 10:16 ` Vladimir Sementsov-Ogievskiy
2015-06-10 13:24 ` Stefan Hajnoczi
2015-06-11 10:19 ` Vladimir Sementsov-Ogievskiy
2015-06-11 13:03 ` Stefan Hajnoczi
2015-06-11 16:21 ` John Snow
2015-06-12 10:28 ` Stefan Hajnoczi
2015-06-12 15:19 ` John Snow
2015-06-10 15:34 ` Kevin Wolf
2015-06-11 10:25 ` Vladimir Sementsov-Ogievskiy
2015-06-11 16:30 ` John Snow
2015-06-12 8:33 ` Kevin Wolf
2015-08-24 10:46 ` Vladimir Sementsov-Ogievskiy
2015-08-24 13:30 ` Vladimir Sementsov-Ogievskiy
2015-08-24 14:08 ` Vladimir Sementsov-Ogievskiy
2015-08-24 14:04 ` Vladimir Sementsov-Ogievskiy
2015-08-31 22:21 ` Eric Blake
2015-08-31 22:24 ` John Snow
2015-06-08 15:21 ` [Qemu-devel] [PATCH 2/8] qcow2: add dirty-bitmaps feature Vladimir Sementsov-Ogievskiy
2015-06-09 16:52 ` Stefan Hajnoczi
2015-06-10 14:30 ` Stefan Hajnoczi
2015-06-12 19:02 ` John Snow
2015-06-15 14:42 ` Stefan Hajnoczi
2015-06-23 17:57 ` John Snow
2015-06-24 9:39 ` Stefan Hajnoczi
2015-08-14 17:14 ` Vladimir Sementsov-Ogievskiy
2015-08-26 9:09 ` Stefan Hajnoczi
2015-06-11 23:04 ` John Snow
2015-06-15 14:05 ` Vladimir Sementsov-Ogievskiy
2015-06-15 16:53 ` John Snow
2015-06-12 21:55 ` John Snow
2015-08-26 13:15 ` Vladimir Sementsov-Ogievskiy
2015-08-26 14:14 ` Vladimir Sementsov-Ogievskiy
2015-08-27 12:43 ` Vladimir Sementsov-Ogievskiy
2015-06-08 15:21 ` [Qemu-devel] [PATCH 3/8] block: store persistent dirty bitmaps Vladimir Sementsov-Ogievskiy
2015-06-08 15:21 ` [Qemu-devel] [PATCH 4/8] block: add bdrv_load_dirty_bitmap Vladimir Sementsov-Ogievskiy
2015-06-09 16:01 ` Stefan Hajnoczi
2015-06-10 22:33 ` John Snow
2015-06-11 10:41 ` Vladimir Sementsov-Ogievskiy
2015-06-08 15:21 ` [Qemu-devel] [PATCH 5/8] qcow2: add qcow2_dirty_bitmap_delete_all Vladimir Sementsov-Ogievskiy
2015-06-08 15:21 ` [Qemu-devel] [PATCH 6/8] qcow2: add autoclear bit for dirty bitmaps Vladimir Sementsov-Ogievskiy
2015-06-09 15:49 ` Stefan Hajnoczi
2015-06-09 15:50 ` Stefan Hajnoczi
2015-08-27 7:45 ` Vladimir Sementsov-Ogievskiy
2015-08-31 11:06 ` Vladimir Sementsov-Ogievskiy
2015-08-31 22:39 ` Eric Blake
2015-08-31 22:50 ` Eric Blake
2015-06-10 23:42 ` John Snow
2015-06-11 8:35 ` Kevin Wolf
2015-06-11 10:49 ` Vladimir Sementsov-Ogievskiy
2015-06-11 16:36 ` John Snow
2015-06-08 15:21 ` [Qemu-devel] [PATCH 7/8] qemu: command line option " Vladimir Sementsov-Ogievskiy
2015-06-11 20:57 ` John Snow
2015-06-12 21:49 ` John Snow
2015-06-08 15:21 ` [Qemu-devel] [PATCH 8/8] iotests: test internal persistent dirty bitmap Vladimir Sementsov-Ogievskiy
2015-06-09 16:17 ` Eric Blake
2015-06-10 15:27 ` [Qemu-devel] [PATCH v2 RFC 0/8] block: persistent dirty bitmaps Stefan Hajnoczi
2015-06-11 11:22 ` Vladimir Sementsov-Ogievskiy
2015-06-11 13:14 ` Stefan Hajnoczi
2015-06-11 20:06 ` Stefan Hajnoczi [this message]
2015-06-12 9:58 ` Denis V. Lunev
2015-06-12 10:36 ` Stefan Hajnoczi
2015-08-26 6:26 ` Vladimir Sementsov-Ogievskiy
2015-08-26 9:13 ` Stefan Hajnoczi
2015-06-12 19:34 ` John Snow
2015-06-17 14:29 ` Vladimir Sementsov-Ogievskiy
2015-06-24 0:21 ` John Snow
2015-07-08 12:24 ` Vladimir Sementsov-Ogievskiy
2015-07-08 15:21 ` John Snow
2015-08-27 10:08 ` Vladimir Sementsov-Ogievskiy
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