From: Zdenek Kabelac <zdenek.kabelac@gmail.com>
To: LVM general discussion and development <linux-lvm@redhat.com>,
Zhiyong Ye <yezhiyong@bytedance.com>,
Zdenek Kabelac <zkabelac@redhat.com>
Subject: Re: [linux-lvm] The feasibility of implementing an alternative snapshot approach
Date: Fri, 6 Jan 2023 14:42:22 +0100 [thread overview]
Message-ID: <2b1466c2-f545-d06a-6ce4-d420ed038ad1@gmail.com> (raw)
In-Reply-To: <d2c5bef2-a418-049e-1ff8-160375881e90@bytedance.com>
Dne 04. 01. 23 v 17:12 Zhiyong Ye napsal(a):
> Hi Zdenek,
>
> Thank you for your reply.
>
> Snapshots of thinlv are indeed more efficient compared to standard lv, this is
> because data blocks can be shared between snapshot and original thinlv. But
> there is also a performance loss after thinlv creates a snapshot. This is
> because the first write to the snapshotted thinlv requires not only allocating
> a new chunk but also copying the old data.
>
> Here are some performance data and a discussion of the thinlv snapshot:
>
> https://listman.redhat.com/archives/linux-lvm/2022-June/026200.html
>
Well that's our current 'state-of-the-art' solution.
Make sure you are using latest kernels for your performance testing - there
have been several improvements around the locking (6+ kernels) - but if this
still not good enough for your case you might need to seek for some other
solutions (although would be nice to know who handles this task better).
Definitely the old 'thick-snapshot' is mostly in maintenance phase and it's
usability (and its design) is limited for some short living temporary
snapshoting (i.e. you are making backup and after completing your backup of
the filesystem you remove your temporary snapshot - it's been never designed
to be used for multi-level multi-GiB snapshots - this will not fly...
When you use thin snapshots - make sure your metadata LV is located on your
fast device and you use best fitting chunksize.
Regards
Zdenek
_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
next prev parent reply other threads:[~2023-01-06 13:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-04 8:00 [linux-lvm] The feasibility of implementing an alternative snapshot approach Zhiyong Ye
2023-01-04 14:09 ` Zdenek Kabelac
2023-01-04 16:12 ` Zhiyong Ye
2023-01-06 13:42 ` Zdenek Kabelac [this message]
2023-01-09 6:21 ` Zhiyong Ye
2023-01-09 22:18 ` Zdenek Kabelac
2023-01-10 3:48 ` [linux-lvm] [External] " Zhiyong Ye
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=2b1466c2-f545-d06a-6ce4-d420ed038ad1@gmail.com \
--to=zdenek.kabelac@gmail.com \
--cc=linux-lvm@redhat.com \
--cc=yezhiyong@bytedance.com \
--cc=zkabelac@redhat.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;
as well as URLs for NNTP newsgroup(s).