From: Dylan Whyte <d.whyte@proxmox.com>
To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>,
Alwin Antreich <a.antreich@proxmox.com>
Subject: Re: [pve-devel] [PATCH docs 2/2] ceph: add explanation on the pg autoscaler
Date: Fri, 15 Jan 2021 15:19:25 +0100 (CET) [thread overview]
Message-ID: <13732644.52.1610720366269@webmail.proxmox.com> (raw)
In-Reply-To: <20210115131716.243126-2-a.antreich@proxmox.com>
Sorry, I didn't prefix the other reply with a comment. Anyway, everything was pretty much fine, I just had some little issues. With this, I have some even more minor issues.
> On 15.01.2021 14:17 Alwin Antreich <a.antreich@proxmox.com mailto:a.antreich@proxmox.com > wrote:
>
>
> Signed-off-by: Alwin Antreich <a.antreich@proxmox.com mailto:a.antreich@proxmox.com >
> ---
> pveceph.adoc | 36 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
>
> diff --git a/pveceph.adoc b/pveceph.adoc
> index 42dfb02..da8d35e 100644
> --- a/pveceph.adoc
> +++ b/pveceph.adoc
> @@ -540,6 +540,42 @@ pveceph pool destroy <name>
> NOTE: Deleting the data of a pool is a background task and can take some time.
> You will notice that the data usage in the cluster is decreasing.
>
> +
> +PG Autoscaler
> +~~~~~~~~~~~~~
> +
> +The PG autoscaler allows the cluster to consider the amount of (expected) data
> +stored in each pool and to choose the appropriate pg_num values automatically.
> +
> +You may need to activate the PG autoscaler module before adjustments can take
> +effect.
> +[source,bash]
> +----
> +ceph mgr module enable pg_autoscaler
> +----
> +
> +The autoscaler is configured on a per pool basis and has the following modes:
> +
> +[horizontal]
> +warn:: A health warning is issued if the suggested `pg_num` value is too
> +different from the current value.
>
s/is too different/differs too much/
(note: "too different" seems grammatically correct but something sounds strange about it here. It could just be a personal thing..)
> +on:: The `pg_num` is adjusted automatically with no need for any manual
> +interaction.
> +off:: No automatic `pg_num` adjustments are made, no warning will be issued
>
s/made, no/made, and no/
> +if the PG count is far from optimal.
> +
> +The scaling factor can be adjusted to facilitate future data storage, with the
> +`target_size`, `target_size_ratio` and the `pg_num_min` options.
> +
> +WARNING: By default, the autoscaler considers tuning the PG count of a pool if
> +it is off by a factor of 3. This will lead to a considerable shift in data
> +placement and might introduce a high load on the cluster.
> +
> +You can find a more in-depth introduction to the PG autoscaler on Ceph's Blog -
> +https://ceph.io/rados/new-in-nautilus-pg-merging-and-autotuning/[New in
> +Nautilus: PG merging and autotuning].
> +
> +
> [[pve_ceph_device_classes]]
> Ceph CRUSH & device classes
> ---------------------------
> --
> 2.29.2
>
>
>
> _______________________________________________
> pve-devel mailing list
> pve-devel@lists.proxmox.com mailto:pve-devel@lists.proxmox.com
> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
>
next prev parent reply other threads:[~2021-01-15 14:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-15 13:17 [pve-devel] [PATCH docs 1/2] docs: ceph: explain pool options Alwin Antreich
2021-01-15 13:17 ` [pve-devel] [PATCH docs 2/2] ceph: add explanation on the pg autoscaler Alwin Antreich
2021-01-15 14:19 ` Dylan Whyte [this message]
2021-01-15 14:05 ` [pve-devel] [PATCH docs 1/2] docs: ceph: explain pool options Dylan Whyte
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=13732644.52.1610720366269@webmail.proxmox.com \
--to=d.whyte@proxmox.com \
--cc=a.antreich@proxmox.com \
--cc=pve-devel@lists.proxmox.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox