From: Santiago Castillo Oli <scastillo@aragon.es>
To: Coly Li <colyli@suse.de>
Cc: linux-bcache@vger.kernel.org
Subject: Re: Low hit ratio and cache usage
Date: Fri, 4 Jun 2021 14:35:56 +0200 [thread overview]
Message-ID: <62f20c57-d502-c362-da84-61a47c891e6d@aragon.es> (raw)
In-Reply-To: <4cc064bc-36f3-cb15-0240-610a45e49300@suse.de>
Hi Coli!
El 04/06/2021 a las 14:05, Coly Li escribió:
> What is the kernel version and where do you have the kernel ? And what
> is the workload on your machine ?
I'm using debian 10 with default debian kernel (4.19.0-16-amd64) in host
and guests.
For virtualization I'm using KVM.
There is a host, where bcache is running. The filesystem over bcache
device is ext4. In that filesystem there is only 9 qcow2 files user by
three VM guests. Two VM are running small nextcloud instances, another
one is running transmission (bittorrent) for feeding debian and other
distro iso files (30 files - 60 GiB approx.)
> Most of the read requests are missing, so they will read from backing
> device and refilled into cache device as used-and-clean data. Once there
> is no enough space to hold more read-cached data, garbage colleague may
> retire the used-and-clean data very fast and make available room for new
> refilling read data. The 19GB data might be existing data from last time gc.
Is it possible to know GC last execution time?
Regards and thank you.
--
___________________________________________________________
next prev parent reply other threads:[~2021-06-04 12:36 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-04 11:07 Low hit ratio and cache usage Santiago Castillo Oli
2021-06-04 12:05 ` Coly Li
2021-06-04 12:35 ` Santiago Castillo Oli [this message]
2021-06-04 12:59 ` Coly Li
2021-06-04 15:56 ` Kai Krakow
[not found] ` <f25c7f91-433e-d699-c1f6-7e828023167f@orange.fr>
2021-06-04 12:12 ` Santiago Castillo Oli
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