[linux-lvm] cache on SSD makes system unresponsive

[Xen]

matthew patton schreef op 20-10-2017 2:12:
>> It is just a backup server,
> 
> Then caching is pointless.

That's irrelevant and not up to another person to decide.

> Furthermore any half-wit caching solution
> can detect streaming read/write and will deliberately bypass the
> cache.

The problem was not performance, it was stability.

> Furthermore DD has never been a useful benchmark for anything.
> And if you're not using 'odirect' it's even more pointless.

Performance was not the issue, stability was.

>> Server has 2x SSD drives by 256Gb each
> 
> and for purposes of 'cache' should be individual VD and not waste
> capacity on RAID1.

Is probably also going to be quite irrelevant to the problem at hand.

>> 10x 3Tb drives.  In addition  there are two
>> MD1200 disk arrays attached with 12x 4Tb disks each.  All
> 
> Raid5 for this size footprint is NUTs. Raid6 is the bare minimum.

That's also irrelevant to the problem at hand.