Den ons 28 apr. 2021 kl 04:25 skrev Xuehan Xu <xxhdx1985126@xxxxxxxxx>: > There is a RAID HBA in each of the machines in our clusters, to which > all SATA disks are attached. We configured the RAID HBA cache mode to > "write through", but, as I checked yesterday, the BBU of the RAID HBAs > are not charged. I'm not quite sure whether the BBU has something to > do with the data loss, as far as I know, all data should be persisted > to the underlying disk before acknowledging upper layer systems when > cache mode is "write through". Am I missing anything? Thanks:-) If the raid card was good, it would change caching strategy when/if the BBU has no power left, but if it didn't and "it was good when we last booted up", then it is possible that it 'promised' that writing to BBU-backed RAM was ok for ack'ing the writes even if they are not on disk yet, and when the BBU failed (for whatever reason), then this promise was not honored and lots of writes were lost. -- May the most significant bit of your life be positive. _______________________________________________ Dev mailing list -- dev@xxxxxxx To unsubscribe send an email to dev-leave@xxxxxxx
