[linux-lvm] Quick Question RE Snapshots

[linux-lvm] Quick Question RE Snapshots

[Ryan Anderson]

[-- Attachment #1: Type: text/plain, Size: 538 bytes --]

I'm sure this has been covered before, but I didn't see it in the
archive: Is a near 90% drop in write performance "normal" snapshot
behavior? If so, :(

If not, are there any good resources I should be looking at? Every
search I perform comes up with one of two types of articles on the matter:


1) Snapshots are  awesome! They let you...(list of really nifty things)

2) Snapshots suck! My system is completely useless while they're active!

-- 
Ryan Anderson
(901) 843 9300
Systems Engineer
WorldSpice Technologies


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 260 bytes --]

Re: [linux-lvm] Quick Question RE Snapshots

[Larry Dickson]

[-- Attachment #1: Type: text/plain, Size: 1133 bytes --]

In my experience yes - if you are doing long sequential writes, snapshot
turns them into random IO. If you were doing short random writes to begin
with, then snapshot should not have such a huge relative effect, because the
non-snapshot performance is already slow.

Larry Dickson
Cutting Edge Networked Storage

On 10/27/09, Ryan Anderson <ryan@worldspice.net> wrote:

> I'm sure this has been covered before, but I didn't see it in the
> archive: Is a near 90% drop in write performance "normal" snapshot
> behavior? If so, :(
>
> If not, are there any good resources I should be looking at? Every
> search I perform comes up with one of two types of articles on the matter:
>
>
> 1) Snapshots are  awesome! They let you...(list of really nifty things)
>
> 2) Snapshots suck! My system is completely useless while they're active!
>
> --
> Ryan Anderson
> (901) 843 9300
> Systems Engineer
> WorldSpice Technologies
>
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>
>

[-- Attachment #2: Type: text/html, Size: 1661 bytes --]