Mirror Break

[YOGI_3]

Hello all..
sorry to put SUN query here..
i dont know the SUN forum URL.

At the mo we have 3 state db's on slice 7 of c0t0d0 disk, we should have had 3 copies on c0t1d0 (the mirror)

We have lost c0t0d0 (the format command is reporting the disk as not available) which means we have lost the mirrors db's.

the OS is up (just) as it is running on the mirror, but because there are no dbs to record any transactions to, the stability of the OS is compromised.

A reboot will loose us both disks!, we considered trying to back up the disk whilst it is still up, but as the loss of the db's is interfering with the operating systems stability, we are sure that any backup taken would be corrupted.



The only real option available would be to rebuild the server from scratch. this would ensure a clean and stable platform for integration.

I am also making changes to the Jumpstart server to ensure that this problem is not inherent in future builds.

some work will need to be done to also protect the other pits3 servers from the same fate.





5. Creating State Database :

State meta database , metadb , keeps information of the metadevices and is needed for Disksuite operation . Disksuite can not function without metadb so a copy of replica databases is placed on different disks to ensure that a copy is available in case of a complete disk failure .

Metadb needs a dedicated disk slice so create partitions of about 5 Meg. on the disks for metadb. If there is no space available for metadb then it can be taken from swap . Having metadb on two disks can create problems as DISKSUITE looks for database replica number > 50% of total replicas and if one of the two disks crashes the replica falls at 50% . On next reboot system will go to single user mode and one has to recreate additional replicas to correct the metadb errors.

The following command creates three replicas of metadb on three disk slices.

#metadb -a -f -c 3 /dev/dsk/c0t1d0s6 /dev/dsk/c0t2d0s6 /dev/dsk/c0t3d0s6
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I WILL BE VERY THANKSFUL IF ANYONE GIVES ME SOLUTION FOR THIS....
if not ossible in SUN, how would have overcome if the same problem comes in hpux
eagerly waiting for replies

yogesh

[Paul F. Carlson · Accepted solution]

Do I understand you correctly that there are no state db's on the good disk (c0t1d0)? Is there a slice avaiable for a state db (c0t1d0s7)?

If you run "metadb -i" and "metastat", what do the output of those show?

I seems like you should be able to run "metadb -a -f -c 3 /dev/dsk/c0t1d0s7" and create state db's on the good disk.