nas stopped recognising 3 hard drives on bootup and says drive bays are empty

[jwills70]

TERRAMASTER T9-423 9-Bay

ok this week i shut down my nas upon restarting it cant see 3 of the hard drives

disk 5,7,8 it says are empty drives which they are not and of coarse it cant see the pool storage

if I take out the disks then slide back in they show as now available but empty which they are not so no pool shows and tells me to create one

if I then turn off the nas and turn back on exactly the same problem the 3 drives have gone again

if when I reinsert the drives and just select reboot from the operating system it shuts down reboots and the drives are all showing and the storage pool is back

any ideas??? what is going on
also, all drives show as healthy

[TMeric]

Could you please provide the specific version of your TOS system? How many disks in total are used by your T9-423? Could you move other disks that are displaying normally to disks 5, 7, and 8 to see if they function correctly?

[jwills70]

Could you please provide the specific version of your TOS system? How many disks in total are used by your T9-423? Could you move other disks that are displaying normally to disks 5, 7, and 8 to see if they function correctly?

i have 9 disks in total being used
tos 5.1.67

ok i had a spare 18tb it works but took it out about 2 months ago as it was failing it could not stay running for more than 4 days then would degrared

so i took out disk 8 just to try as you suggested and replaced with the spare and everything worked well of coarse it says pool degraded and to rebuild so fingers crossed i struck lucky and choose the correct one out the 3 i got a hd 18tb coming today so will use that

if i rember correctly i just place the new one in slot 8 and it automnaticly repairs or do i have to do something to start the rebuild ??

[jwills70]

ok it appears to be working after switching one of the drives out its currently resyncing my next problem is


tnas TERRAMASTER T9-423 9-Bay
operating system 5.0.1.67

ok i have a TERRAMASTER D6-320 6 bay usb enclosure
and a TERRAMASTER D5-300C USB3.1 5 bay enclosure

everything was working ok then I needed to change over a hard drive on the t9 nas to fix a degraded pool so before doing anything I switched of the 2 USB enclosers with the 11 USB disks inside and started the rebuilding of the pool

now upon switching the USB enclosures back on it appears 2 are not showing for some reason the letters that start with sd_ then the letter for some reason now start at sd_d then sd_e then jumps to sd_m misses a few more letters then goes up to z

I presume the letters can only go up to z then it hits maximum so it does not matter which 2 drives I pull as soon as it goes straight to z the remaining 2 won't work

so how do I release the letters so I can use my drives again ie sd_e being next instead of jumping like 8 letters and then more after m

I have tried using safe eject and just shutting the enclosures down no matter what its not releasing the letters