Re: Very slow performance on Sharded GlusterFS

[<gencer@xxxxxxxxxxxxx>]

Hi Krutika,

 

Have you be able to look out my profiles? Do you have any clue, idea or suggestion?

 

Thanks,

-Gencer

 

From: Krutika Dhananjay [mailto:kdhananj@xxxxxxxxxx]
Sent: Friday, June 30, 2017 3:50 PM
To: gencer@xxxxxxxxxxxxx
Cc: gluster-user <gluster-users@xxxxxxxxxxx>
Subject: Re: Very slow performance on Sharded GlusterFS

 

Just noticed that the way you have configured your brick order during volume-create makes both replicas of every set reside on the same machine.

That apart, do you see any difference if you change shard-block-size to 512MB? Could you try that?

If it doesn't help, could you share the volume-profile output for both the tests (separate)?

Here's what you do:

1. Start profile before starting your test - it could be dd or it could be file download.

# gluster volume profile <VOL> start

2. Run your test - again either dd or file-download.

3. Once the test has completed, run `gluster volume profile <VOL> info` and redirect its output to a tmp file.

4. Stop profile

# gluster volume profile <VOL> stop

And attach the volume-profile output file that you saved at a temporary location in step 3.

-Krutika

 

On Fri, Jun 30, 2017 at 5:33 PM, <gencer@xxxxxxxxxxxxx> wrote:

Hi Krutika,

 

Sure, here is volume info:

 

root@sr-09-loc-50-14-18:/# gluster volume info testvol

 

Volume Name: testvol

Type: Distributed-Replicate

Volume ID: 30426017-59d5-4091-b6bc-279a905b704a

Status: Started

Snapshot Count: 0

Number of Bricks: 10 x 2 = 20

Transport-type: tcp

Bricks:

Brick1: sr-09-loc-50-14-18:/bricks/brick1

Brick2: sr-09-loc-50-14-18:/bricks/brick2

Brick3: sr-09-loc-50-14-18:/bricks/brick3

Brick4: sr-09-loc-50-14-18:/bricks/brick4

Brick5: sr-09-loc-50-14-18:/bricks/brick5

Brick6: sr-09-loc-50-14-18:/bricks/brick6

Brick7: sr-09-loc-50-14-18:/bricks/brick7

Brick8: sr-09-loc-50-14-18:/bricks/brick8

Brick9: sr-09-loc-50-14-18:/bricks/brick9

Brick10: sr-09-loc-50-14-18:/bricks/brick10

Brick11: sr-10-loc-50-14-18:/bricks/brick1

Brick12: sr-10-loc-50-14-18:/bricks/brick2

Brick13: sr-10-loc-50-14-18:/bricks/brick3

Brick14: sr-10-loc-50-14-18:/bricks/brick4

Brick15: sr-10-loc-50-14-18:/bricks/brick5

Brick16: sr-10-loc-50-14-18:/bricks/brick6

Brick17: sr-10-loc-50-14-18:/bricks/brick7

Brick18: sr-10-loc-50-14-18:/bricks/brick8

Brick19: sr-10-loc-50-14-18:/bricks/brick9

Brick20: sr-10-loc-50-14-18:/bricks/brick10

Options Reconfigured:

features.shard-block-size: 32MB

features.shard: on

transport.address-family: inet

nfs.disable: on

 

-Gencer.

 

From: Krutika Dhananjay [mailto:kdhananj@xxxxxxxxxx]
Sent: Friday, June 30, 2017 2:50 PM
To: gencer@xxxxxxxxxxxxx
Cc: gluster-user <gluster-users@xxxxxxxxxxx>
Subject: Re: Very slow performance on Sharded GlusterFS

 

Could you please provide the volume-info output?

-Krutika

 

On Fri, Jun 30, 2017 at 4:23 PM, <gencer@xxxxxxxxxxxxx> wrote:

Hi,

 

I have an 2 nodes with 20 bricks in total (10+10).

 

First test:

 

2 Nodes with Distributed – Striped – Replicated (2 x 2)

10GbE Speed between nodes

 

“dd” performance: 400mb/s and higher

Downloading a large file from internet and directly to the gluster: 250-300mb/s

 

Now same test without Stripe but with sharding. This results are same when I set shard size 4MB or 32MB. (Again 2x Replica here)

 

Dd performance: 70mb/s

Download directly to the gluster performance : 60mb/s

 

Now, If we do this test twice at the same time (two dd or two doewnload at the same time) it goes below 25/mb each or slower.

 

I thought sharding is at least equal or a little slower (maybe?) but these results are terribly slow.

 

I tried tuning (cache, window-size etc..). Nothing helps.

 

GlusterFS 3.11 and Debian 9 used. Kernel also tuned. Disks are “xfs” and 4TB each.

 

Is there any tweak/tuning out there to make it fast?

 

Or is this an expected behavior? If its, It is unacceptable. So slow. I cannot use this on production as it is terribly slow.

 

The reason behind I use shard instead of stripe is i would like to eleminate files that bigger than brick size.

 

Thanks,

Gencer.

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