January 23Jan 23 I have an array with a max disk size of 2 TB... 5 disks are the exact same size (identical bytes and sectors). I saved one of those drives (same size) to use as a parity disk.... but it is giving me an error saying it is "Stopped. Disk in parity slot is not biggest.".... anyone know why this would be?Array disks:root@unRAID-VM:/dev# for x in cat /root/2; do fdisk -l $x | grep sectors; done Disk sdab: 1.82 TiB, 2000398934016 bytes, 3907029168 sectorsDisk sdy: 1.82 TiB, 2000398934016 bytes, 3907029168 sectorsDisk sdx: 1.82 TiB, 2000398934016 bytes, 3907029168 sectorsDisk sdr: 1.82 TiB, 2000398934016 bytes, 3907029168 sectorsDisk sdt: 1.82 TiB, 2000398934016 bytes, 3907029168 sectorsNew Parity Disk (failing):root@unRAID-VM:/dev# fdisk -l sdaa | grep sectors Disk sdaa: 1.82 TiB, 2000398934016 bytes, 3907029168 sectors
January 23Jan 23 Author Gladly (see attached)... however, it seems to me like all the info needed to confirm this parity drive is, indeed, at least the same size or bigger than any other drive in the array.... and I don't mean this sarcastically, I genuinely want to know if you expect you will find some additional / contradictory information in the troubleshooting capture compared to what I included in my screenshots above, I genuinely want to know so I know where to look for all the relevant information needed when I run into a problem in the future.Just based on the screenshots I put in my first post (which shows all 5 array drives and the parity drive are identical, both in byte and sector count), based on that as a premis, this drive should be eligible to fill the parity drive role, correct? I just want to make sure I understand how this should be working and that it's not something simple that I overlooked / misunderstood.Thanksunraid-vm-diagnostics-20260122-2336.zip
January 23Jan 23 Community Expert Solution New parity is an SSD, for performance reasons, Unraid partitions SSDs starting @ 1MiB, while HDDs are partitioned @ 32KiB, so the current partition on the HDDs will be slightly larger.I've not tried this recently, but possibly, if you really want to use the SSD as parity, which may not be a great idea, since it will have to handle the writes for all disks combined, and it cannot be trimmed, you may be able to get Unraid to accept it if you precreate the partition on the same sector as the HDDs:Unassign the device, make sure it's still /dev/sdaa or adjust the commandsfdisk --quiet --label dos /dev/sdaa <<< 'start=64'Reassign the device.And test, I'm not sure if this still works in the current version.
January 23Jan 23 Author Out of curiosity, what would the downside to using an SSD for parity be (or is it still a valid concern) if the array is just going to be used as a media file storage location....i.e. write once, read many.... for many very large files..... so not re-writing data (almost ever), just streaming writes, once, then streaming (one) read at a time when watching a movie...I don't see the downside to an SSD in that scenario, do you? That said, now that I understand the limitation, I will just swap the SSD for a platter drive for parity, since it doesn't really matter (for the same reasons).But I have to say, this is nother situation that would be super easy to actually notify the user with some useful debug/failure messages (about the different partitioning approach from one drive type to another), which would prevent frustration on my end and unnecessary support tickets on your end where you have to repeatedly answer the same question over and over.Why do they seem so opposed to useful debug info to help the users troubleshoot on their own??
January 23Jan 23 Community Expert 1 minute ago, infinisean said:Out of curiosity, what would the downside to using an SSD for parity be (or is it still a valid concern) if the array is just going to be used as a media file storage location....If it's WORM data, much less of a concern, still you need to account that the SSD wil get the same writes as all the 22 devices combined, so recommend using a good brand and a more top-of-the-line model, or it may start being slower than a disk, since most current SSDs, have a pseudo SLC cache, and once that is full, they will be much slower, since parity doesn't have a filesystem and cannot be trimmed; the device will always be "full" after the initial sync.
January 23Jan 23 Author Yea, the "no trim on array SSDs" thing is.... not ideal. but it's not really worth debating since they will likely never implement that for what they see as a very minor percentage of their user base who stands to benefit from it.Plenty of other places / features that would be higher on the priority list to try and get implemented.I do still have one open issue from another topic, if you could possibly help with that....I have a drive that unraid said was "missing" from the array.... but it is still accessible and functioning (mount, read, etc.) just fine.Yet no matter what I do, I can't get that drive to show up in the drop-down menu when assigning drives to slots..... so I can't use it.How can I reset what unraid is "seeing" that it believes that drive is not a valid potential drive to add? I have no idea how to reset or override that "decision" or even where to look.
January 23Jan 23 Community Expert 17 minutes ago, infinisean said:I have a drive that unraid said was "missing" from the array.... but it is still accessible and functioning (mount, read, etc.) just fine.Please post the diagnostics.
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