6 Apr
2020
6 Apr
'20
11:20 p.m.
Is not there a way to Deal with this kind of setup when playing with the
"weight" of an OSD? I dont mean the "crush weight".
I am in a Situation where i had to Think about to add a Server with 24 x 2TB disks - my
other osd nodes has 12 x 4TB. Which is in Sum 48TB per node in both situations.
Am 31. März 2020 18:10:24 MESZ schrieb Anthony D'Atri <aad(a)dreamsnake.net>et>:
You can adjust the Primary Affinity down on the larger
drives so
they’ll get less read load. In one test I’ve seen this result in a
10-15% increase in read throughout but it depends on your situation.
Optimal settings would require calculations that make my head hurt,
maybe someone has a tool but I haven’t seen it.
You might want to ensure that the drives are spread evenly across your
(unspecified) failure domains so that the extra capacity isn’t wasted,
again depending on your topology.
On Mar 31, 2020, at 8:49 AM, Eneko Lacunza
<elacunza(a)binovo.es>
wrote:
Hi Andras,
> El 31/3/20 a las 16:42, Andras Pataki escribió:
> I'm looking for some advice on what to do about drives of different
sizes
in the same cluster.
>
> We have so far kept the drive sizes consistent on our main ceph
cluster (using
8TB drives). We're getting some new hardware with
larger, 12TB drives next, and I'm pondering on how best to configure
them. If I just simply add them, they will have 1.5x the data (which
is less of a problem), but will also get 1.5x the iops - so I presume
it will slow the whole cluster down as a result (these drives will be
busy, and the rest will not be as much). I'm wondering how people
generally handle this.
>
> I'm more concerned about these larger drives being busier than the
rest -
so I'd like to be able to put for example 1/3 drive of less
accessed data on them in addition to the usual data - to use the extra
capacity but not increase the load on them. Is there an easy way to
accomplish this? One possibility is to run two OSDs on the drive (in
two crush hierarchies), which isn't ideal. Can I just run one OSD
somehow and put it into two crush roots, or something similar?
You should adjust the weight of the new 12TB disk
OSDs, to match the
weight of the current 8TB OSDs.
That will make the new disks the same as the old disks to Ceph :-)
But you'll
lost the extra 4TB space, until you remove the 8TB disks
from the cluster...
Cheers
Eneko
--
Zuzendari Teknikoa / Director Técnico
Binovo IT Human Project, S.L.
Telf. 943569206
Astigarragako bidea 2, 2º izq. oficina 11; 20180 Oiartzun (Gipuzkoa)
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