Dne 21.10.2017 v 16:33 Oleg Cherkasov napsal(a):
On 20. okt. 2017 21:35, John Stoffel wrote:
"Oleg" == Oleg Cherkasov <o1e9@member.fsf.org> writes:
Oleg> On 19. okt. 2017 21:09, John Stoffel wrote:
Oleg> RAM 12Gb, swap around 12Gb as well. /dev/sda is a hardware RAID1, the
Oleg> rest are RAID5.
Interesting, it's all hardware RAID devices from what I can see.
It is exactly what I wrote initially in my first message!
Can you should the *exact* commands you used to make the cache? Are
you using lvcache, or bcache? they're two totally different beasts.
I looked into bcache in the past, but since you can't remove it from
an LV, I decided not to use it. I use lvcache like this:
I have used lvcache of course and here are commands from bash history:
lvcreate -L 1G -n primary_backup_lv_cache_meta primary_backup_vg /dev/sda5
### Allocate ~247G ib /dev/sda5 what has left of VG
lvcreate -l 100%FREE -n primary_backup_lv_cache primary_backup_vg /dev/sda5
lvconvert --type cache-pool --cachemode writethrough --poolmetadata
primary_backup_vg/primary_backup_lv_cache_meta
primary_backup_vg/primary_backup_lv_cache
lvconvert --type cache --cachepool primary_backup_vg/primary_backup_lv_cache
primary_backup_vg/primary_backup_lv
### lvconvert failed because required some extra extends in VG so I had to
reduce cache LV and try again:
lvreduce -L 200M primary_backup_vg/primary_backup_lv_cache
Hi
Without plans to interrupt thoughts on topic here - the explanation here is
very simple.
Cache pool is made from 'data' & 'metadata' LV - so both needs some space.
In the case of 'cache pool' it's pretty good plan to have both device is fast
spindle (SSD).
So can you please provide output of:
lvs -a -o+devices
so it could be easily validated both _cdata & _cmeta LV is hosted by some SSD
device (it's not shown anywhere in the thread - so just to be sure we have
them on right disks)
Regards
Zdenek
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