1) If i want to use cache tier should i use it with ssd journaling or i can get better perfomance using more ssd GB for cache tier?
2) I've got cluster made of 26x900GB SAS disk with ssd journaling. The placement groups i've got is 1024. When i add new osd to cluster, my VMs get io errors and got stuck even if i had osd_max_backfills set to 1. If i change pgs from 1024 to 4096 would it get less affected by backfilling and recovery?
3) When i was adding my last 6 drives to a cluster i've noticed that the recovery speed had gone from 500-1000MB/s to 10-50 MB/s. When i restarted the osd that i was adding the transfers got back to normal. Also i've noticed that when i then do rados benchmark i've got dropping transfers to 0 MB/s even few times a row. The restarting osdes that i was adding or one by one that was already in cluster solved the problem. What can it be ? In the logs there isn't anything weird. The whole cluster stucks till i restart or even recreate journals on them. How to solve this ?
Please help me.
Best regards !
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