[Gluster-users] Shard Volume testing (3.7.5)

[Krutika Dhananjay]

----- Original Message -----

> From: "Lindsay Mathieson" <lindsay.mathieson at gmail.com>
> To: "Krutika Dhananjay" <kdhananj at redhat.com>
> Cc: "gluster-users" <gluster-users at gluster.org>
> Sent: Wednesday, October 28, 2015 1:08:33 PM
> Subject: Re: [Gluster-users] Shard Volume testing (3.7.5)

> On 28 October 2015 at 17:03, Krutika Dhananjay < kdhananj at redhat.com > wrote:

> > So sharding also helps with better disk utilization in
> > distributed-replicated
> > volumes for large files (like VM images).
> 
> > ..
> 
> > There are other long-term benefits one could reap from using sharding: for
> > instance, for someone who might want to use tiering in VM store use-case,
> > having sharding will be beneficial in terms of only migrating the shards
> > between hot and cold tiers, as opposed to moving large files in full, even
> > if only a small portion of the file is changed/accessed. :)
> 

> Interesting points, thanks.

> > > > Yes. So Paul Cuzner and Satheesaran who have been testing sharding here
> > > > have
> > > > reported better write performance with 512M shards. I'd be interested
> > > > to
> > > > know what you feel about performance with relatively larger shards
> > > > (think
> > > > 512M).
> > > 
> > 
> 

> > > Seq Read speeds basically tripled, and seq writes improved to the limit
> > > of
> > > the network connection.
> > 
> 

> > OK. And what about the data heal performance with 512M shards?
> > Satisfactory?
> 

> Easily satisfactory, a bit slower than the 4MB shard but still way faster
> than a full multi GB file heal :)

> Something I have noticed, is that the heal info (gluster volume heal
> <datastore> info) can be very slow to return, as in many 10's of seconds -
> is there a way to speed that up?

With sharding? Or even otherwise? Approximately how many entries did the command list when you found it to be slow? 
On a related note, Anuradha (cc'd) is working on an enhancement that would make the 'heal info' reporting faster. She should be able to tell you more about it. 

> It would be every useful if there was a command that quickly gave
> summary/progress status, e.g "There are <X> shards to be healed"

Hmmm ... that would have to be an extension of 'heal info' or perhaps post-processing of the 'heal info' output which would group the different shards of a given file that need heal together. Nice suggestion. I will think about it. 

-Krutika 

> --
> Lindsay
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