[Gluster-users] GlusterFS Changing Hash of Large Files?
ravishankar at redhat.com
Mon Jul 29 04:35:27 UTC 2019
An even replica count is prone to split-brains with the default quorum
settings, so replica 3 is recommended.
But a replica 4 setup should not cause any checksum change if one node
is unreachable, as long as the reads/writes are done via the gluster
mount (and not directly the bricks). I wasn't able to re-create this
when I copied a huge file on to a 1x4 volume (glusterfs 6.3) with one of
the bricks down. Is this something that you can reproduce? Do you see
anything suspicious in the mount or brick logs?
On 28/07/19 10:47 AM, Strahil wrote:
> I never thought that replica 4 is allowed optiion. I always thought
> that 3 copies is the maximum.
> Best Regards,
> Strahil Nikolov
> On Jul 27, 2019 16:30, Matthew Evans <runmatt at live.com> wrote:
> Hi Ravishankar - I figured out the issue. The 4th node was showing
> "online" under 'gluster peer status' as well as 'gluster volume
> status' - but 'gluster volume status' wasn't showing a TCP port
> for that 4th node. When I opened 49152 in firewalld and then
> re-copied the ISO, the hash didn't change.
> So, now I guess the question would be, why would having one
> malfunctioning node override 3 functioning nodes and cause a file
> to be altered? I wasn't performing the initial copy onto the
> malfunctioning node.
> matt at docker1:~$ sudo glusterfs --version
> glusterfs 6.3
> matt at docker1:~$ sudo gluster volume info
> Volume Name: swarm-vols
> Type: Replicate
> Volume ID: 0b51e6b3-786e-454e-8a16-89b47e94828a
> Status: Started
> Snapshot Count: 0
> Number of Bricks: 1 x 4 = 4
> Transport-type: tcp
> Brick1: docker1:/gluster/data
> Brick2: docker2:/gluster/data
> Brick3: docker3:/gluster/data
> Brick4: docker4:/gluster/data
> Options Reconfigured:
> performance.client-io-threads: off
> nfs.disable: on
> transport.address-family: inet
> auth.allow: 10.5.22.*
> *From:* Ravishankar N <ravishankar at redhat.com>
> *Sent:* Saturday, July 27, 2019 2:04 AM
> *To:* Matthew Evans <runmatt at live.com>; gluster-users at gluster.org
> <gluster-users at gluster.org>
> *Subject:* Re: [Gluster-users] GlusterFS Changing Hash of Large
> On 26/07/19 6:50 PM, Matthew Evans wrote:
> I've got a new glusterfs 4 node replica cluster running under
> CentOS 7. All hosts are backed by SSD drives and are
> connected to a 1Gbps Ethernet network. 3 nodes are running on
> CentOS 7 under ESXi on the same physical host, 1 is running on
> CentOS 7 under Hyper-V. I use this for my docker swarm
> persistent storage and all seems to work well.
> Yesterday however, I copied a 4GB .ISO file to my volume for a
> friend to download. I noticed the SHA256 hash of the ISO was
> altered. I downloaded a fresh copy to my desktop, verified the
> hash, scp'd it to the local glusterfs host storage and again,
> re-verified the hash. The moment I copied it to my glusterfs
> volume, the file hash changed. When my friend downloaded the
> ISO, his hash matched changed hash.
> Can you provide the below details?
> - glusterfs version
> -`gluster volume info`
> I am new to glusterfs, having deployed this as my first
> cluster ever about a week ago. Can someone help me work
> through why this file
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