[ceph-users] Consequences of setting bluestore_fsck_quick_fix_on_mount to false?

Hi, Looking at the Octopus upgrade instructions, I see "the first time each OSD starts, it will do a format conversion to improve the accounting for “omap” data. This may take a few minutes to as much as a few hours (for an HDD with lots of omap data)." and that I can disable this by setting bluestore_fsck_quick_fix_on_mount to false. A couple of questions about this: i) what are the consequences of turning off this "quick fix"? Is it possible to have it run in the background or similar? ii) is there any way to narrow down the time estimate? Our production cluster has 3060 OSDs on hdd (with block.db on NVME), and obviously 3000 lots of "a few hours" is an awful lot of time... I'll be doing some testing on our test cluster (by putting 10M objects into an S3 bucket before trying the upgrade), but it'd be useful to have some idea of how this is likely to work at scale... Thanks, Matthew -- The Wellcome Sanger Institute is operated by Genome Research Limited, a charity registered in England with number 1021457 and a company registered in England with number 2742969, whose registered office is 215 Euston Road, London, NW1 2BE.