From: Stefan Hajnoczi <stefanha@redhat.com>
To: Maged Mokhtar <mmokhtar@petasan.org>
Cc: Ilya Dryomov <idryomov@gmail.com>,
Dongsheng Yang <dongsheng.yang@easystack.cn>,
ceph-devel@vger.kernel.org, vromanso@redhat.com,
kwolf@redhat.com, mimehta@redhat.com, acardace@redhat.com
Subject: Re: rbd kernel block driver memory usage
Date: Thu, 26 Jan 2023 16:51:57 -0500 [thread overview]
Message-ID: <Y9L1/fK6M0Co4q9a@fedora> (raw)
In-Reply-To: <b7021070-0d40-362c-51ab-666922c153a6@petasan.org>
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On Thu, Jan 26, 2023 at 08:14:22PM +0200, Maged Mokhtar wrote:
> in case of object map which the driver loads, takes 2 bits per 4 MB of image
> size. 16 TB image requires 1 MB of memory.
>
> > > I was trying to get a sense ofwhether to look deeper into the rbd driver in a OOM kill scenario.
>
> If you are looking into OOM, maybe look into lowering queue_depth which you can specify when you map the image. Technically it belongs to the block layer queue rather than the rbd driver itself, If you write 4MB block size and your queue_depth is 1000, you need 4GB memory for inflight data for that single image, if you have many images it could add up.
Thanks!
Stefan
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next prev parent reply other threads:[~2023-01-26 21:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-25 16:57 rbd kernel block driver memory usage Stefan Hajnoczi
2023-01-26 13:48 ` Ilya Dryomov
2023-01-26 14:36 ` Stefan Hajnoczi
2023-01-26 15:49 ` Anthony D'Atri
2023-01-27 9:58 ` Ilya Dryomov
2023-01-26 18:14 ` Maged Mokhtar
2023-01-26 21:51 ` Stefan Hajnoczi [this message]
2023-01-27 9:40 ` Maged Mokhtar
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