Add udev-md-raid-safe-timeouts.rules (#32)

These udev rules attempt to set a safe kernel controller timeout for disks containing RAID level 1 or higher partitions for commodity disks which do not have SCTERC capability, or do have it but it is disabled.

No attempt is made to change the STCERC settings on devices which support it.

This attempts to mitigate the problem described here:

    https://raid.wiki.kernel.org/index.php/Timeout_Mismatch
    http://strugglers.net/~andy/blog/2015/11/09/linux-software-raid-and-drive-timeouts/

where the kernel controller may timeout on a read from a disk after the default timeout of 30 seconds and consequently cause mdraid to regard the disk as dead and eject it from the RAID array.

The mitigation is to set the timeout to 180 seconds for disks which contain a RAID level 1 or higher partition.
You can view, comment on, or merge this pull request online at:

https://github.com/neilbrown/mdadm/pull/32

-- Commit Summary --

* Add udev-md-raid-safe-timeouts.rules

-- File Changes --

A udev-md-raid-safe-timeouts.rules (61)

-- Patch Links --

https://github.com/neilbrown/mdadm/pull/32.patch
https://github.com/neilbrown/mdadm/pull/32.diff

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This pull request appeared on my github mdadm ... thing.

I haven't looked in detail. If someone would like to review it or something, that would be nice.

Thanks,
NeilBrown

Quoted 41 lines · jonathanunderwood

These udev rules attempt to set a safe kernel controller timeout for disks containing RAID level 1 or higher partitions for commodity disks which do not have SCTERC capability, or do have it but it is disabled.

No attempt is made to change the STCERC settings on devices which support it.

This attempts to mitigate the problem described here:

    https://raid.wiki.kernel.org/index.php/Timeout_Mismatch
    http://strugglers.net/~andy/blog/2015/11/09/linux-software-raid-and-drive-timeouts/

where the kernel controller may timeout on a read from a disk after the default timeout of 30 seconds and consequently cause mdraid to regard the disk as dead and eject it from the RAID array.

The mitigation is to set the timeout to 180 seconds for disks which contain a RAID level 1 or higher partition.
You can view, comment on, or merge this pull request online at:

https://github.com/neilbrown/mdadm/pull/32

-- Commit Summary --

* Add udev-md-raid-safe-timeouts.rules

-- File Changes --

A udev-md-raid-safe-timeouts.rules (61)

-- Patch Links --

https://github.com/neilbrown/mdadm/pull/32.patch
https://github.com/neilbrown/mdadm/pull/32.diff

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Reply to this email directly or view it on GitHub:
https://github.com/neilbrown/mdadm/pull/32

Quoted 5 lines · NeilBrown

This pull request appeared on my github mdadm ... thing.

I haven't looked in detail. If someone would like to review it or something, that would be nice.

Finally got around to looking at this. I am not hugely familiar with smartctl, but it looks reasonable to me, especially since they won't be auto-installed.

Jonathan, please make sure to always CC linux-raid on all mdadm related patches. Note I prefer patches to git pull requests.

Quoted 11 lines · Jes Sorensen

Quoted 5 lines · NeilBrown

This pull request appeared on my github mdadm ... thing.

I haven't looked in detail. If someone would like to review it or something, that would be nice.

Finally got around to looking at this. I am not hugely familiar with smartctl, but it looks reasonable to me, especially since they won't be auto-installed.

Quoted 2 lines

Jonathan, please make sure to always CC linux-raid on all mdadm related patches. Note I prefer patches to git pull requests.

Will do, thanks for the heads up. Let me know if you need anything further for this patch.