Asustor and JBOD

[soter]

Hi forum. I have a question. If I have 4 disk in a JBOD and one disk fails, can I still access the remaining data on the 3 other disks?

[orion]

Basically, no. However if you are familiar with Linux commands, you might be able to recover certain of data.

[father.mande]

Hi,

Hi forum. I have a question. If I have 4 disk in a JBOD and one disk fails, can I still access the remaining data on the 3 other disks?

JBOD have NO security it's "Just a Bunch Of Disks"
... the major problem is (compare to 4 single disk (as your case)) that a logical volume JBOD manage the disks, so space are NOT managed as single disk

You must try to recover it using external Linux tool generally provide as USB Live
... if your model can start using an USB drive (all with Bios ... so x86/x86_64) ... you can try using it on the NAS itself
... if not you must use an external system with 4 slots disk BUT attention order of disk is important
... ... first disk of the JBOD contain the partition table for all (so knowing the faulty disk position change the type of recover (partition can be more difficult to rebuild))
... ... last disk are mostly lot of /00 inside (hex. dump tool help you) ... for the intermediate it's more complex to know the position
... ... AFTER reorder (if you don't know the real order) the disk depend of the file system (ex. if F.S. use superblock the superblock are ordered ... so easy)
... ... last (before starting recovery) is to determine the limit on disk of each partition partner of the JBOD (a first shift from start of disk, then the real size of the partition (in your case I expect only one)
... ... based on this value you can try to recover data

I don't suggest you to try if you are not confirmed in Linux management, but if you don't have backup (if you have you win time and money to rebuild all) you can try asking to specialized company in recover.

If you rebuild all, I can suggest you to forget JBOD and move to Raid or Single (just a little more management ... but the 3 others disks can be used without constraints ... and recovery of a single disk is more easy and quick.

In all case : Raid, JBOD, Single can add for Raid security BUT are not backup ... so you MUST have a backup (full or at least the most important data.
also JBOD must be reserved for very specific usage (perhaps your case) ... due to the difficulty of recovering (except if use ON an existing Raid or LVM)

Good luck.

Philippe.
N.B. my own experience (recover) was on real Linux server not on NAS ... so perhaps some things can be better or worst ... and on ext4 file system ... not BTRFS (BTRFS having the advantage of snapshot)