3ware RAID - what exactly does "INIT ARRAY" mean?
A friend of mine has a server with a 3ware RAID card (8506-4LP) with 4x 300GB drives configured in RAID5 giving 900GB usable. The system actually boots from a single IDE drive. There was a power failure and now when his server boots, the RAID card BIOS shows up "INIT ARRAY" next to the 900GB. When he pressed ALT-3 to go into the 3ware setup screen, it offered to "INIT" the array on pressing F8. My friend got scared when he saw this and quickly powered the server off :-) I've Googled a bit, and what I find seems to imply that the controller detected the unclean shutdown and "only" wants to recalculate the parity bits on the array. This shouldn't involve ANY loss of data. On the other hand, INIT sounds like it might mean "format the array and destroy all the data" :-( There is apparently 800GB of data on this thing, and although my friend has backups, he'd rather not have to go through an 800GB restore. I can see why. Anyone had the "INIT ARRAY" message from a 3ware controller before? Anyone know what it really means? ;-) Thanks-in-advance, Jim
On Fri, Mar 24, 2006 at 08:08:37AM +0100, Sbs Bofh wrote:
A friend of mine has a server with a 3ware RAID card (8506-4LP) with 4x 300GB drives configured in RAID5 giving 900GB usable. The system actually boots from a single IDE drive.
There was a power failure and now when his server boots, the RAID card BIOS shows up "INIT ARRAY" next to the 900GB. When he pressed ALT-3 to go into the 3ware setup screen, it offered to "INIT" the array on pressing F8.
Anyone had the "INIT ARRAY" message from a 3ware controller before? Anyone know what it really means? ;-)
Looking up the user manual on the 3ware site gives this: Auto initialization on power failure A power failure will cause the secondary drive of a mirrored unit (RAID 1 or 10) to degrade. To make sure that the information on both drives is accurate, initialization of the unit starts automatically in the background. When the initialization is complete, the two halves of the mirror are redundant again. 3ware's auto-init feature determines if this is required. During driver startup, a flag is set that indicates that the driver loaded. Upon an orderly shutdown, the flag is rewritten, indicating that there was a clean shutdown. During the next system power cycle the firmware queries the flag. If there was a power failure, the flag will indicate that there was not a clean shutdown. This means that the data on the drives may not be correct. For a RAID 5 configuration, if the process encounters the flag setting that indicates a power failure, the firmware automatically starts the background initialization process to calculate and write the parity information. -- David Smith Work Email: Dave.Smith@st.com STMicroelectronics Home Email: David.Smith@ds-electronics.co.uk Bristol, England GPG Key: 0xF13192F2
At 09:12 PM 24/03/2006, David SMITH wrote:
On Fri, Mar 24, 2006 at 08:08:37AM +0100, Sbs Bofh wrote:
A friend of mine has a server with a 3ware RAID card (8506-4LP) with 4x 300GB drives configured in RAID5 giving 900GB usable. The system actually boots from a single IDE drive.
There was a power failure and now when his server boots, the RAID card BIOS shows up "INIT ARRAY" next to the 900GB. When he pressed ALT-3 to go into the 3ware setup screen, it offered to "INIT" the array on pressing F8.
Anyone had the "INIT ARRAY" message from a 3ware controller before? Anyone know what it really means? ;-)
Looking up the user manual on the 3ware site gives this:
Auto initialization on power failure
A power failure will cause the secondary drive of a mirrored unit (RAID 1 or 10) to degrade. To make sure that the information on both drives is accurate, initialization of the unit starts automatically in the background. When the initialization is complete, the two halves of the mirror are redundant again. 3ware's auto-init feature determines if this is required. During driver startup, a flag is set that indicates that the driver loaded. Upon an orderly shutdown, the flag is rewritten, indicating that there was a clean shutdown. During the next system power cycle the firmware queries the flag. If there was a power failure, the flag will indicate that there was not a clean shutdown. This means that the data on the drives may not be correct. For a RAID 5 configuration, if the process encounters the flag setting that indicates a power failure, the firmware automatically starts the background initialization process to calculate and write the parity information.
I'l add:- ref raid5 - suppose to but has been known not too happen if NOT all the drives have the flag set (loss of power while in the middle of a write to drive function) this happens ocassionally if the read/write times across all drives are not in very tight tollerances such as origonally having raid0 / 1 and changing to raid5 by adding drives. regards scsijon
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scsijon