[linux-lvm] cache on SSD makes system unresponsive

[Xen]

Oleg Cherkasov schreef op 20-10-2017 10:21:
> On 19. okt. 2017 20:13, Xen wrote:
>> 
>> The main cause was a way too slow SSD but at the same time... that 
>> sorta thing still shouldn't happen, locking up the entire system.
>> 
>> I haven't had a chance to try again with a faster SSD.
> 
> I have double checked with MegaRAID/CLI and all disks on that rig
> (including SSD ones of course) are SAS 6Gb/s both devices and links.
> My first thought about those SSDs was that those are slower than RAID5
> however it seems not the case.
> 
> Could it be TRIMing issue because those are from 2012?

You mean that the SATA version is too low to interleave TRIMs with data 
access?

Because I think that was the case with my mSata SSD.

I don't currently remember the sata version that allowed interleaving 
but that SSD didn't reach or have it.

After trimming performance would go up greatly.

So I don't know about SAS but it might be similar right.