From: Paolo Bonzini <pbonzini@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>,
qemu-devel@nongnu.org,
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Subject: Re: [Qemu-devel] [PATCH 00/17] Support mismatched host and guest logical block sizes
Date: Wed, 14 Dec 2011 12:47:15 +0100 [thread overview]
Message-ID: <4EE88CC3.7090903@redhat.com> (raw)
In-Reply-To: <4EE884BD.4090808@redhat.com>
On 12/14/2011 12:13 PM, Kevin Wolf wrote:
> As we discussed before, the really interesting point here is defaults,
> and whatever you choose to do is wrong in some respect.
>
> So it looks like you chose to make the virtual device default to the
> host block size.
... wait wait, I default to 512. :)
Here is the rationale. 512-over-4k may be slow, but is safe (but it is
not slow if you align partitions properly). 4k-over-512 is unsafe. So,
defaulting to 512 seemed the right thing after all.
Paolo
next prev parent reply other threads:[~2011-12-14 11:47 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-13 12:37 [Qemu-devel] [PATCH 00/17] Support mismatched host and guest logical block sizes Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 01/17] block: do not rely on open_flags for bdrv_is_snapshot Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 02/17] block: store actual flags in bs->open_flags Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 03/17] block: pass protocol flags up to the format Paolo Bonzini
2011-12-15 4:10 ` Zhi Yong Wu
2011-12-13 12:37 ` [Qemu-devel] [PATCH 04/17] block: non-raw protocols never cache Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 05/17] block: remove enable_write_cache Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 06/17] block: move flag bits together Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 07/17] raw: remove the aligned_buf Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 08/17] block: rename buffer_alignment to guest_block_size Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 09/17] block: add host_block_size Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 10/17] raw: probe host_block_size Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 11/17] iscsi: save host block size Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 12/17] block: allow waiting only for overlapping writes Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 13/17] block: allow waiting at arbitrary granularity Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 14/17] block: protect against "torn reads" for guest_block_size > host_block_size Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 15/17] block: align and serialize I/O when guest_block_size < host_block_size Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 16/17] block: default physical block size to host block size Paolo Bonzini
2011-12-13 12:37 ` [Qemu-devel] [PATCH 17/17] qemu-io: add blocksize argument to open Paolo Bonzini
2011-12-14 11:13 ` [Qemu-devel] [PATCH 00/17] Support mismatched host and guest logical block sizes Kevin Wolf
2011-12-14 11:47 ` Paolo Bonzini [this message]
2011-12-14 12:05 ` Kevin Wolf
2011-12-14 12:40 ` Paolo Bonzini
2011-12-21 16:55 ` Christoph Hellwig
2011-12-21 17:00 ` Paolo Bonzini
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