[Discussion] RAID 5 Smart bad sector on drive warning - Replace/Upgrade & NVMe hypercache sizing
Posted: 03 Dec 2025, 03:59
I encountered warning errors on one of my drives in a RAID 5 configuration. I also found the system frequently rebooting itself. I installed some NVMes and moved the "system drives" to them and the frequency of unexpected shutdown/reboots was reduced significantly.
I moved as much as I could to the new Volumes on the NVMes, like sytem drives, applications, logs, and any docker containers, etc. Only "pure" data storage which is only added to about once every week or two, for basically "warm" storage remained on the RAID 5 array. And again unexpected shutdowns and reboots were much less common, going from usually within every 24 hours, to 7 days and counting with zero issue.
I also wanted to say how easy it was to remove the drive with the SMART/bad sector warning in the GUI, pop it out of the enclosure, insert a new drive, and add the new drive to the array to rebuild/resync it - Which should take about 50 hours to resync ~20TBs.
Then I plan to do the same remove, disconnect, and reconnect a new bigger drive, and then resync, for each of the other drives to make available much more space to expand the RAID 5 array into. Currently I expect it will take a total of a few hundred hours until fully complete.
So 2 things.
1 - Why is a drive with bad sectors not able to properly mark them as bad and prevent rebooting/system instability?
2 - Why can't the hyper cache on the NVMes be designated a more reasonable size like 1-200 GB? Forced to use the entire NVMe ( possibly, multiple terrabytes ) and not be able to use the NVMes for system drives, seems like a big miss.
I moved as much as I could to the new Volumes on the NVMes, like sytem drives, applications, logs, and any docker containers, etc. Only "pure" data storage which is only added to about once every week or two, for basically "warm" storage remained on the RAID 5 array. And again unexpected shutdowns and reboots were much less common, going from usually within every 24 hours, to 7 days and counting with zero issue.
I also wanted to say how easy it was to remove the drive with the SMART/bad sector warning in the GUI, pop it out of the enclosure, insert a new drive, and add the new drive to the array to rebuild/resync it - Which should take about 50 hours to resync ~20TBs.
Then I plan to do the same remove, disconnect, and reconnect a new bigger drive, and then resync, for each of the other drives to make available much more space to expand the RAID 5 array into. Currently I expect it will take a total of a few hundred hours until fully complete.
So 2 things.
1 - Why is a drive with bad sectors not able to properly mark them as bad and prevent rebooting/system instability?
2 - Why can't the hyper cache on the NVMes be designated a more reasonable size like 1-200 GB? Forced to use the entire NVMe ( possibly, multiple terrabytes ) and not be able to use the NVMes for system drives, seems like a big miss.
