Re: deleting objects from a pool

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This is a dangerous command because it can remove all your objects. At least it can only do one namespace at a time. It was intended to cleanup rados bench runs, and is dangerous because it doesn't require extra hoops like rados rmpool does.

I'm tempted to disallow a usage this way with empty --prefix/--run-name arguments.

David

On 6/25/15 10:40 PM, Podoski, Igor wrote:
Hi David,

You're right, now I see adding --run-name "" will clean all benchmark data from specified namespace, so you can run command only once.

rados -p <poolname> -N <namespace> cleanup --prefix "" --run-name ""

Regards,
Igor.


-----Original Message-----
From: David Zafman [mailto:dzafman@xxxxxxxxxx]
Sent: Friday, June 26, 2015 3:46 AM
To: Podoski, Igor; Deneau, Tom; Dałek, Piotr; ceph-devel
Subject: Re: deleting objects from a pool


If you have rados bench data around, you'll need to run cleanup a second time because the first time the "benchmark_last_metadata" object will be consulted to find what objects to remove.

Also, using cleanup this way will only remove objects from the default namespace unless a namespace is specified with the -N option.

rados -p <poolname> -N <namespace> cleanup --prefix ""

David

On 6/24/15 11:06 PM, Podoski, Igor wrote:
Hi,

It appears, that cleanup can be used as a purge:

rados -p <poolname> cleanup  --prefix ""

Regards,
Igor.


-----Original Message-----
From: ceph-devel-owner@xxxxxxxxxxxxxxx
[mailto:ceph-devel-owner@xxxxxxxxxxxxxxx] On Behalf Of Deneau, Tom
Sent: Wednesday, June 24, 2015 10:22 PM
To: Dałek, Piotr; ceph-devel
Subject: RE: deleting objects from a pool

I've noticed that deleting objects from a basic k=2 m=1 erasure pool is much much slower than deleting a similar number of objects from a replicated size 3 pool (so the same number of files to be deleted).   It looked like the ec pool object deletion was almost 20x slower.  Is there a lot more work to be done to delete an ec pool object?

-- Tom



-----Original Message-----
From: ceph-devel-owner@xxxxxxxxxxxxxxx [mailto:ceph-devel-
owner@xxxxxxxxxxxxxxx] On Behalf Of Dalek, Piotr
Sent: Wednesday, June 24, 2015 11:56 AM
To: ceph-devel
Subject: Re: deleting objects from a pool

-----Original Message-----
From: ceph-devel-owner@xxxxxxxxxxxxxxx [mailto:ceph-devel-
owner@xxxxxxxxxxxxxxx] On Behalf Of Deneau, Tom
Sent: Wednesday, June 24, 2015 6:44 PM

I have benchmarking situations where I want to leave a pool around
but delete a lot of objects from the pool.  Is there any really fast
way to do
that?
I noticed rados rmpool is fast but I don't want to remove the pool.

I have been spawning multiple threads, each deleting a subset of the
objects
(which I believe is what rados bench write does) but even that can
be very slow.
For now, apart from "rados -p <poolname> cleanup" (which doesn't
purge the pool, but merely removes objects written during last
benchmark run), the only option is by brute force:

for i in $(rados -p <poolname> ls); do (rados -p <poolname> rm $i
&>/dev/null &); done;

There's no "purge pool" command in rados -- not yet, at least. I was
thinking about one, but never really had time to implement one.

With best regards / Pozdrawiam
Piotr Dałek
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