[Gluster-users] Brick Reboot => VMs slowdown, client crashes

Carl Sirotic csirotic at evoqarchitecture.com
Fri Aug 23 22:06:16 UTC 2019


so it means, at least I am not getting the expected behavior and there 
is hope.

I put the quorum settings that I was told a couple of emails ago.

After applying virt group, they are

cluster.quorum-type auto
cluster.quorum-count (null)
cluster.server-quorum-type server
cluster.server-quorum-ratio 0
cluster.quorum-reads no


I just put the ping timeout to 5 seconds now.


On 2019-08-23 5:45 p.m., Ingo Fischer wrote:
> Hi Carl,
> In my understanding and experience (I have a replica 3 System running 
> too) this should not happen. Can you tell your client and server 
> quorum settings?
> Ingo
> Am 23.08.2019 um 15:53 schrieb Carl Sirotic 
> <csirotic at evoqarchitecture.com <mailto:csirotic at evoqarchitecture.com>>:
>> However,
>> I must have misunderstood the whole concept of gluster.
>> In a replica 3, for me, it's completely unacceptable, regardless of 
>> the options, that all my VMs go down when I reboot one node.
>> The whole purpose of having a full 3 copy of my data on the fly is 
>> suposed to be this.
>> I am in the process of sharding every file.
>> But even if the healing time would be longer, I would still expect a 
>> non-sharded replica 3 brick with vm boot disk, to not go down if I 
>> reboot one of its copy.
>> I am not very impressed by gluster so far.
>> Carl
>> On 2019-08-19 4:15 p.m., Darrell Budic wrote:
>>> /var/lib/glusterd/groups/virt is a good start for ideas, notably 
>>> some thread settings and choose-local=off to improve read 
>>> performance. If you don’t have at least 10 cores on your servers, 
>>> you may want to lower the recommended shd-max-threads=8 to no more 
>>> than half your CPU cores to keep healing from swamping out regular 
>>> work.
>>> It’s also starting to depend on what your backing store and 
>>> networking setup are, so you’re going to want to test changes and 
>>> find what works best for your setup.
>>> In addition to the virt group settings, I use these on most of my 
>>> volumes, SSD or HDD backed, with the default 64M shard size:
>>> performance.io <http://performance.io>-thread-count: 32# seemed good 
>>> for my system, particularly a ZFS backed volume with lots of spindles
>>> client.event-threads: 8
>>> cluster.data-self-heal-algorithm: full# 10G networking, uses more 
>>> net/less cpu to heal. probably don’t use this for 1G networking?
>>> performance.stat-prefetch: on
>>> cluster.read-hash-mode: 3# distribute reads to least loaded server 
>>> (by read queue depth)
>>> and these two only on my HDD backed volume:
>>> performance.cache-size: 1G
>>> performance.write-behind-window-size: 64MB
>>> but I suspect these two need another round or six of tuning to tell 
>>> if they are making a difference.
>>> I use the throughput-performance tuned profile on my servers, so you 
>>> should be in good shape there.
>>>> On Aug 19, 2019, at 12:22 PM, Guy Boisvert 
>>>> <guy.boisvert at ingtegration.com 
>>>> <mailto:guy.boisvert at ingtegration.com>> wrote:
>>>> On 2019-08-19 12:08 p.m., Darrell Budic wrote:
>>>>> You also need to make sure your volume is setup properly for best 
>>>>> performance. Did you apply the gluster virt group to your volumes, 
>>>>> or at least features.shard = on on your VM volume?
>>>> That's what we did here:
>>>> gluster volume set W2K16_Rhenium cluster.quorum-type auto
>>>> gluster volume set W2K16_Rhenium network.ping-timeout 10
>>>> gluster volume set W2K16_Rhenium auth.allow \*
>>>> gluster volume set W2K16_Rhenium group virt
>>>> gluster volume set W2K16_Rhenium storage.owner-uid 36
>>>> gluster volume set W2K16_Rhenium storage.owner-gid 36
>>>> gluster volume set W2K16_Rhenium features.shard on
>>>> gluster volume set W2K16_Rhenium features.shard-block-size 256MB
>>>> gluster volume set W2K16_Rhenium cluster.data-self-heal-algorithm full
>>>> gluster volume set W2K16_Rhenium performance.low-prio-threads 32
>>>> tuned-adm profile random-io        (a profile i added in CentOS 7)
>>>> cat /usr/lib/tuned/random-io/tuned.conf
>>>> ===========================================
>>>> [main]
>>>> summary=Optimize for Gluster virtual machine storage
>>>> include=throughput-performance
>>>> [sysctl]
>>>> vm.dirty_ratio = 5
>>>> vm.dirty_background_ratio = 2
>>>> Any more optimization to add to this?
>>>> Guy
>>>> -- 
>>>> Guy Boisvert, ing.
>>>> IngTegration inc.
>>>> http://www.ingtegration.com
>>>> https://www.linkedin.com/in/guy-boisvert-8990487
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