Even though the diff is about two video files, it seems like running snapraid sync is effectively recreating the parity information, since the operation still has 17 more hours to go at 48%. Is this normal? I would have thought since the actual diff is trivial then sync would be fast even if I add a drive to the array. Did I do anything wrong or is there any way I could have expedited the sync? Can someone explain why adding an empty drive requires the parity info to be completely recreated like this?
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No, this is not normal. If you add a drive to the configuration file and this drive is empty snapraid sync should be instantaneous. It definitely should not have to recreate all the parity data.
I doubt that the two added video files can be the cause of this heavy sync either.
Were you running snapraid sync using the -F argument? Or did you add this new disk as a parity disk instead of a data disk?
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I am just using the standard snapraid sync command. I am looking back over my config and it looks correct to me. It's not a complicated setup for me, originally it was 2x8TB for data and another 8TB for parity. I ran out of storage and had an old 3TB drive sitting around so I added that. Just looking at the activity lights for my drives, the 3TB I recently added isn't even really being accessed that much during the sync, just the original 8TB drives that were pretty much already full.
Upon reflection, I think I know what I did wrong. I probably can't use the -R argument and then interrupt that sync (CTRL+C) and then run snapraid sync again without the -R. The sync command seems to resume any previous incomplete sync rather than restart. So once I run snapraid sync -R, I'm "stuck" rebuilding the parity even if I interrupt that sync, aren't I?
Whatever the case at this point I'll just have to let it finish. I wish I could figure out what I did wrong but I'll keep in mind next time that it shouldn't take this long.
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I know it costs me nothing to suggest but would a y/n confirmation in this context not be appropriate? It seems like sync -R or sync -F are essentially destructive actions since it seems like I basically destroyed/overwrote my parity data. I went from near-complete parity to temporarily having no parity at all. I didn't have a clear concept of the mistake I was making until it bit me. Was there anything I could have done after running sync -R to undo my mistake?
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Even though the diff is about two video files, it seems like running snapraid sync is effectively recreating the parity information, since the operation still has 17 more hours to go at 48%. Is this normal? I would have thought since the actual diff is trivial then sync would be fast even if I add a drive to the array. Did I do anything wrong or is there any way I could have expedited the sync? Can someone explain why adding an empty drive requires the parity info to be completely recreated like this?
No, this is not normal. If you add a drive to the configuration file and this drive is empty snapraid sync should be instantaneous. It definitely should not have to recreate all the parity data.
I doubt that the two added video files can be the cause of this heavy sync either.
Were you running snapraid sync using the -F argument? Or did you add this new disk as a parity disk instead of a data disk?
I am just using the standard snapraid sync command. I am looking back over my config and it looks correct to me. It's not a complicated setup for me, originally it was 2x8TB for data and another 8TB for parity. I ran out of storage and had an old 3TB drive sitting around so I added that. Just looking at the activity lights for my drives, the 3TB I recently added isn't even really being accessed that much during the sync, just the original 8TB drives that were pretty much already full.
Upon reflection, I think I know what I did wrong. I probably can't use the -R argument and then interrupt that sync (CTRL+C) and then run snapraid sync again without the -R. The sync command seems to resume any previous incomplete sync rather than restart. So once I run snapraid sync -R, I'm "stuck" rebuilding the parity even if I interrupt that sync, aren't I?
Whatever the case at this point I'll just have to let it finish. I wish I could figure out what I did wrong but I'll keep in mind next time that it shouldn't take this long.
Yes, yes and you already did.
I know it costs me nothing to suggest but would a y/n confirmation in this context not be appropriate? It seems like sync -R or sync -F are essentially destructive actions since it seems like I basically destroyed/overwrote my parity data. I went from near-complete parity to temporarily having no parity at all. I didn't have a clear concept of the mistake I was making until it bit me. Was there anything I could have done after running sync -R to undo my mistake?
@amadvance or maybe just remove the -R alias (keeping --force-realloc) and add some extra warning / clarification in the manual?
There are not many situations where -R is advisable, so making it a bit harder to do would probably be a good thing.
Hi,
Yes, -R is dangerous, I'll add a more clear warning in the manual.
Instead, -F is safe, as parity is no reallocated.
Ciao,
Andrea