[Top][All Lists]

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

Re: [Qemu-devel] [PATCH v2] doc: Add NBD_CMD_BLOCK_STATUS extension

From: Vladimir Sementsov-Ogievskiy
Subject: Re: [Qemu-devel] [PATCH v2] doc: Add NBD_CMD_BLOCK_STATUS extension
Date: Thu, 7 Apr 2016 13:38:05 +0300
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0

On 05.04.2016 16:43, Paolo Bonzini wrote:

On 05/04/2016 06:05, Kevin Wolf wrote:
The options I can think of is adding a request field "max number of
descriptors" or a flag "only single descriptor" (with the assumption
that clients always want one or unlimited), but maybe you have a better
I think a limit is better.  Even if the client is ultimately going to
process the whole file, it may take a very long time and space to
retrieve all the descriptors in one go.  Rather than query e.g. 16GB at
a time, I think it's simpler to put a limit of 1024 descriptors or so.


I vote for the limit too. More over, I think, there should be two sides limit:

1. The client can specify the limit, so server should not return more extents than requested. Of course, server should chose sequential extents from the beginning of requested range. 2. Server side limit: if client asked too many extents or not specified a limit at all, server should not return all extents, but only 1024 (for ex.) from the beginning of the range. 2.1 And/or, why not allow the server use the power of structured reply and send several reply chunks? Why did you forbid this? (if I correctly understand "This chunk type MUST appear at most once in a structured reply.")

Best regards,

reply via email to

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