Cassandra JBOD has a bunch of issues, so I don't recommend it for production:
1) disks fill up with load (data) unevenly, meaning you can run out on a disk
while some are half-full2) one bad disk can take out the whole node3) instead
of a small failure probability on an LVM/RAID volume, with JBOD you end up near
100% chance of failure after 3 years or so.4) generally you will not have
enough warning of a looming failure with JBOD compared to LVM/RAID.
(Somecompanies take a week or two to replace a failed disk.)
JBOD is easy to setup, but hard to manage. Thanks, James.
From: kurt greaves <k...@instaclustr.com>
To: User <user@cassandra.apache.org>
Sent: Friday, August 17, 2018 5:42 AM
Subject: Re: JBOD disk failure
As far as I'm aware, yes. I recall hearing someone mention tying system tables
to a particular disk but at the moment that doesn't exist.
On Fri., 17 Aug. 2018, 01:04 Eric Evans, <john.eric.ev...@gmail.com> wrote:
On Wed, Aug 15, 2018 at 3:23 AM kurt greaves <k...@instaclustr.com> wrote:
> Yep. It might require a full node replace depending on what data is lost from
> the system tables. In some cases you might be able to recover from partially
> lost system info, but it's not a sure thing.
Ugh, does it really just boil down to what part of `system` happens to
be on the disk in question? In my mind, that makes the only sane
operational procedure for a failed disk to be: "replace the entire
node". IOW, I don't think we can realistically claim you can survive
a failed a JBOD device if it relies on happenstance.
> On Wed., 15 Aug. 2018, 17:55 Christian Lorenz, <christian.lor...@webtrekk.com
> > wrote:
>>
>> Thank you for the answers. We are using the current version 3.11.3 So this
>> one includes CASSANDRA-6696.
>>
>> So if I get this right, losing system tables will need a full node rebuild.
>> Otherwise repair will get the node consistent again.
>
> [ ... ]
--
Eric Evans
john.eric.ev...@gmail.com
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