From: Zdenek Kabelac <zkabelac@redhat.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] How to calculate the LVM SSD cache size?
Date: Tue, 14 Oct 2014 15:27:05 +0200 [thread overview]
Message-ID: <543D24A9.9040907@redhat.com> (raw)
In-Reply-To: <CAAH150aKPX-scGh3QCbOkPxwcH+PSHtLZ47ZMHN84mfQaFTgUA@mail.gmail.com>
Dne 13.10.2014 v 14:20 Kees de Jong napsal(a):
> Hi,
>
>
>
> The documentation is not clear about how big the cache size should be
> for optimal performance. It only gives pointers about how big the meta
> data for the cache should be.
>
> "Create the cache metadata LV. This LV will hold cache pool metadata.
> The size of this LV should be 1000 times smaller than the cache data
> LV, with a minimum size of 8MiB."
>
> There is however an example in the man page with a 100GB OriginLV
> which apparently needs (at least) 10GB of cache size. But what is the
> math? I for example have 4 LV's I want to cache. 6GB, 60GB, 100GB and
> 2TB and I have a 240GB SSD which will act as the caching disk.
>
> Could someone please fill in the gaps here?
>
>
https://github.com/jthornber/thin-provisioning-tools/blob/master/caching/cache_metadata_size.cc
The recent lvm2 tools (git) should maintain the size of metadata device
at proper size for any given cache pool data device size.
Zdenek
next prev parent reply other threads:[~2014-10-14 13:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-13 12:20 [linux-lvm] How to calculate the LVM SSD cache size? Kees de Jong
2014-10-14 13:27 ` Zdenek Kabelac [this message]
2014-10-14 21:23 ` Brassow Jonathan
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