[Gluster-users] Why does this setup not survive a node crash?

Burnash, James jburnash at knight.com
Wed Mar 16 11:07:42 PDT 2011


So - answering myself with the (apparent) solution. The configuration IS correct as shown - the problems were elsewhere.

Primary cause for this seems to be performing the gluster native client mount on a virtual machine WITHOUT using the " -O --disable-direct-io-mode" parameter.

So I was mounting like this:

	mount -t glusterfs jc1letgfs5:/test-pfs-ro1 /test-pfs2

When I should have been doing this:

	mount -t glusterfs -O --disable-direct-io-mode jc1letgfs5:/test-pfs-ro1 /test-pfs2

Secondly, I changed the volume parameter "network.ping-timeout" from its default of 43 to 10 seconds, in order to get faster recovery from a downed storage node:

	gluster volume set pfs-rw1 network.ping-timeout 10

This configuration now survives the loss of either node of the two storage server mirrors. There is a noticeable delay before commands on the mount point complete the first time a command is issued after one of the nodes have gone done - but then they return at the same speed as when all nodes were present.

Thanks especially to all who helped, and Anush who helped me troubleshoot it from a different angle.

James Burnash, Unix Engineering

-----Original Message-----
From: gluster-users-bounces at gluster.org [mailto:gluster-users-bounces at gluster.org] On Behalf Of Burnash, James
Sent: Friday, March 11, 2011 11:31 AM
To: gluster-users at gluster.org
Subject: Re: [Gluster-users] Why does this setup not survive a node crash?

Could anyone else please take a peek at this an sanity check my configuration. I'm quite frankly at a loss and tremendously under the gun ...

Thanks in advance to any kind souls.

James Burnash, Unix Engineering

-----Original Message-----
From: gluster-users-bounces at gluster.org [mailto:gluster-users-bounces at gluster.org] On Behalf Of Burnash, James
Sent: Thursday, March 10, 2011 3:55 PM
To: gluster-users at gluster.org
Subject: [Gluster-users] Why does this setup not survive a node crash?

Perhaps someone will see immediately, given the data below, why this configuration will not survive a crash of one node - it appears that any node crashed out of this set will cause gluster native clients to hang until the node comes back.

Given (2) initial storage servers (CentOS 5.5, Gluster 3.1.1):

Starting out by creating a Replicated-Distributed pair with this command:
gluster volume create test-pfs-ro1 replica 2 jc1letgfs5:/export/read-only/g01 jc1letgfs6:/export/read-only/g01 jc1letgfs5:/export/read-only/g02 jc1letgfs6:/export/read-only/g02

Which ran fine (thought I did not attempt to crash 1 of the pair)

And then adding (2) more servers, identically configured, with this command:
gluster volume add-brick test-pfs-ro1 jc1letgfs7:/export/read-only/g01 jc1letgfs8:/export/read-only/g01 jc1letgfs7:/export/read-only/g02 jc1letgfs8:/export/read-only/g02
Add Brick successful

root at jc1letgfs5:~# gluster volume info

Volume Name: test-pfs-ro1
Type: Distributed-Replicate
Status: Started
Number of Bricks: 4 x 2 = 8
Transport-type: tcp
Bricks:
Brick1: jc1letgfs5:/export/read-only/g01
Brick2: jc1letgfs6:/export/read-only/g01
Brick3: jc1letgfs5:/export/read-only/g02
Brick4: jc1letgfs6:/export/read-only/g02
Brick5: jc1letgfs7:/export/read-only/g01
Brick6: jc1letgfs8:/export/read-only/g01
Brick7: jc1letgfs7:/export/read-only/g02
Brick8: jc1letgfs8:/export/read-only/g02

And this volfile info out of the log file /var/log/glusterfs/etc-glusterd-mount-test-pfs-ro1.log:

[2011-03-10 14:38:26.310807] W [dict.c:1204:data_to_str] dict: @data=(nil)
Given volfile:
+------------------------------------------------------------------------------+
  1: volume test-pfs-ro1-client-0
  2:     type protocol/client
  3:     option remote-host jc1letgfs5
  4:     option remote-subvolume /export/read-only/g01
  5:     option transport-type tcp
  6: end-volume
  7:
  8: volume test-pfs-ro1-client-1
  9:     type protocol/client
 10:     option remote-host jc1letgfs6
 11:     option remote-subvolume /export/read-only/g01
 12:     option transport-type tcp
 13: end-volume
 14:
 15: volume test-pfs-ro1-client-2
 16:     type protocol/client
 17:     option remote-host jc1letgfs5
 18:     option remote-subvolume /export/read-only/g02
 19:     option transport-type tcp
 20: end-volume
 21:
 22: volume test-pfs-ro1-client-3
 23:     type protocol/client
 24:     option remote-host jc1letgfs6
 25:     option remote-subvolume /export/read-only/g02
 26:     option transport-type tcp
 27: end-volume
 28:
 29: volume test-pfs-ro1-client-4
 30:     type protocol/client
 31:     option remote-host jc1letgfs7
 32:     option remote-subvolume /export/read-only/g01
 33:     option transport-type tcp
 34: end-volume
 35:
36: volume test-pfs-ro1-client-5
 37:     type protocol/client
 38:     option remote-host jc1letgfs8
 39:     option remote-subvolume /export/read-only/g01
 40:     option transport-type tcp
 41: end-volume
 42:
 43: volume test-pfs-ro1-client-6
 44:     type protocol/client
 45:     option remote-host jc1letgfs7
 46:     option remote-subvolume /export/read-only/g02
 47:     option transport-type tcp
 48: end-volume
 49:
 50: volume test-pfs-ro1-client-7
 51:     type protocol/client
 52:     option remote-host jc1letgfs8
 53:     option remote-subvolume /export/read-only/g02
 54:     option transport-type tcp
 55: end-volume
 56:
 57: volume test-pfs-ro1-replicate-0
 58:     type cluster/replicate
 59:     subvolumes test-pfs-ro1-client-0 test-pfs-ro1-client-1
 60: end-volume
 61:
 62: volume test-pfs-ro1-replicate-1
 63:     type cluster/replicate
 64:     subvolumes test-pfs-ro1-client-2 test-pfs-ro1-client-3
 65: end-volume
 66:
 67: volume test-pfs-ro1-replicate-2
 68:     type cluster/replicate
 69:     subvolumes test-pfs-ro1-client-4 test-pfs-ro1-client-5
 70: end-volume
 71:
 72: volume test-pfs-ro1-replicate-3
 73:     type cluster/replicate
 74:     subvolumes test-pfs-ro1-client-6 test-pfs-ro1-client-7
 75: end-volume
 76:
 77: volume test-pfs-ro1-dht
 78:     type cluster/distribute
 79:     subvolumes test-pfs-ro1-replicate-0 test-pfs-ro1-replicate-1 test-pfs-ro1-replicate-2 test-pfs-ro1-replicate-3
 80: end-volume
 81:
 82: volume test-pfs-ro1-write-behind
 83:     type performance/write-behind
 84:     subvolumes test-pfs-ro1-dht
 85: end-volume
 86:
 87: volume test-pfs-ro1-read-ahead
 88:     type performance/read-ahead
 89:     subvolumes test-pfs-ro1-write-behind
 90: end-volume
 91:
 92: volume test-pfs-ro1-io-cache
 93:     type performance/io-cache
 94:     subvolumes test-pfs-ro1-read-ahead
 95: end-volume
 96:
 97: volume test-pfs-ro1-quick-read
 98:     type performance/quick-read
 99:     subvolumes test-pfs-ro1-io-cache
100: end-volume
101:
102: volume test-pfs-ro1-stat-prefetch
103:     type performance/stat-prefetch
104:     subvolumes test-pfs-ro1-quick-read
105: end-volume
106:
107: volume test-pfs-ro1
108:     type debug/io-stats
109:     subvolumes test-pfs-ro1-stat-prefetch
110: end-volume

Any input would be greatly appreciated. I'm working beyond my deadline already, and I'm guessing that I'm not seeing the forest for the trees here.

James Burnash, Unix Engineering


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