terastation very slow

[aldar]

Our old TeraStation TS-RXLB08 became very slow.
When we access it via browser before asking for credentials it loads 10-15 minutes with this screen:

then after entering credentials it loads for 10-15 minutes:

Then when we try to do something, session expires.
How to investigate it further?

[oxygen8]

enable email notification
reboot and check the drivestatus
maybe you have a demaged disk
the securest way is to open ssh and start a long selvetest for each drive

[aldar]

The point is that it's too slow.
While it's loading, session expires.
I am unable to login to allow ssh access or email notifications.

[Texturtle]

It's almost certainly a failing drive that the system hasn't detected. If possible, shut it down and pull the drives one at a time and attach them to a PC. Use a program like CrystalDisk Info to pull the SMART information. It is likely this will reveal which drive is failing, then you can just replace that drive.

[aldar]

All hards have smart status "good"
I used crystalDiskInfo to check it.
There are 3 drives in RAID5.
Reports on each drive are here: https://drive.google.com/open?id=19s0pehw4QRLpnf3sxHlsmsQYfy_DfLfB

[oxygen8]

try with firefox

[aldar]

Excuse me, I didn't get.
Firefox browser?

[oxygen8]

Yes