Hello list.
Deep scrub totally kills cluster performance.
First of all, it takes several minutes to complete:
2018-12-09 01:39:53.857994 7f2d32fde700 0 log_channel(cluster) log [DBG] : 4.75 deep-scrub starts
2018-12-09 01:46:30.703473 7f2d32fde700 0 log_channel(cluster) log [DBG] : 4.75 deep-scrub ok
Second, while it runs, it consumes 100% of OSD time[1]. This is on an ordinary 7200RPM spinner.
While this happens, VMs cannot access their disks, and that leads to service interruptions.
I disabled scrub and deep-scrub operations for now, and have 2 major questions:
- can I disable 'health warning' status for noscrub and nodeep-scrub? I thought there was a way to do this, but can't find it. I want my cluster to think it's healthy, so if any new 'slow requests' or anything else pops - it will change status to 'health warning' again;
- is there a way to limit deepscrub impact on disk performance, or do I just have to go and buy SSDs?
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