Monday, 15 April 2013

Quicker fixes are not a good idea (in most cases)

Every once in a while someone comes up with a forum question along the lines of

I have such and such problem with my storage. The data is still accessible, but the storage unit is for some reason in abnormal state. What should I do?

Typical (and proper) answer is
  1. back up data,
  2. test the backup,
  3. make sure the original problem, which caused whatever abnormality there was, is corrected,
  4. rebuild the storage from scratch,
  5. restore data
Often, this is not considered a good enough advice: Is there any quicker way to resolve the issue?

Actually, no. To make sure the abnormal state is properly repaired, one needs to identify all the undesired effects and changes to the data. This is plain impossible in all but most simple cases. So, there is always a risk of missing some important point during "quick" repair, masking the problem instead of repairing it. The issue might then reappear later in some undesired way.

Wednesday, 3 April 2013

Intel RS2MB044 RAID controller

If you have an Intel RS2MB044 controller and get the message

Controller ID: 0 Controller encountered a fatal error and was reset

Flash the latest firmware.

Next thing,

If flashing with the latest firmware fails stating that

Firmware Failed to FLASH flash. Stop!!!
FW error description:
The requested command cannot be completed as the image is corrupted.

Then, start flasing older firmwares first. The update from very old firmware version to the latest one may require several intermediate firmwares to be flashed before the controller will accept the latest one.

Mk. II testbed storage system

Finally, completed the build of Mark II testbed storage array today, to replace aging QNAP TS-639 Pro unit.

Intel RS2MB044 controller.
4x OCZ Solid 3 120 GB SSD, directly connected to the controller.
Intel RES2SV240 expander, connected by SFF-8088 to SFF-8087 cable.
16x 3TB WD Red hard drives connected to the expander.

The hard drives are configured as 14x 3TB RAID 6 and 2x hot spare, for a total of 36 decimal TB unformatted capacity.

SSD cache to be configured later.