[mythtv-users] MySQL recordedseek regularly getting corrupted

[faginbagin]

On 12/1/2016 5:59 AM, Jean-Yves Avenard wrote:
> On 1 December 2016 at 20:50, Gary Buhrmaster <gary.buhrmaster at gmail.com> wrote:
>> On Thu, Dec 1, 2016 at 9:35 AM, Håkon Alstadheim
>> <hakon at alstadheim.priv.no> wrote:
>> .....
>>> Better yet:
>>
>> First, as previously stated, check what directory
>> is being used using the show variables statement.
>> The mysql tmpdir can point anywhere (I seem to
>> recall some early recommendations to set
>> tmpdir at /dev/shm by some before using tmpfs
>> for /tmp became more prevalent).
>
> I did posted the value earlier
> mysql> SHOW VARIABLES LIKE '%tmpdir%';
> +-------------------+-------+
> | Variable_name     | Value |
> +-------------------+-------+
> | slave_load_tmpdir | /tmp  |
> | tmpdir            | /tmp  |
> +-------------------+-------+
> 2 rows in set (0.00 sec)
>
> it's definitely on the SSD
>
> I'm on ubuntu 14.04.
> It has a Intel(R) Xeon(R) CPU E3-1220 v3 @ 3.10GHz; 32GB ECC RAM.
> Main disk is a 128GB Samsung 850 SSD.
>
> / is only used for the service it runs, that is mysql, mythbackend,
> VNC, Azureus and AirVideo HD server.
> Everything else is mounted (all storage groups) via NFSv3 on a FreeNAS
> box (12x4GB WD Red disks, in RAIZ2 configuration, (actually 2xRAIDZ2),
> so 2 redundancy disks for every 6 disks; 4 in total).
>
> This has only occurred since upgrading to Ubuntu 14.04 about 5 months
> ago, where I also took the opportunity to change the SSD from a 64GB
> intel MLC to a 128GB disk and converting the partition to BTRFS.
> Didn't upgrade to 16.04 for multiple reasons:
> 1- I had issues with my mother board
> 2- the ext->btrfs is no longer working in recent kernels.

Seems to me that focusing on where /tmp is, is a waste of time. /tmp may 
be an issue when trying to repair the corruption, but I think what you 
really want is to prevent the corruption, right? If so, I would focus on 
the things that changed when the corruption started to happen. Two 
things come to mind, based on what you've told us:
1) The SSD
2) the btrfs file system
I would try replacing one of those and seeing if that fixes the problem.

Regards,
Helen