Replacing disk controlled by SVM
The following scenario assumes two mirrored disks, with two state database replicas located on slice 7 of both disks. High level steps for this are as follows:
- determine failed disk
- detach failed submirrors
- clear failed submirror metadevices and database replicas from failed disk
- unconfigure the failed disk and replace it
- configure the new disk and recreate VTOC
- add new database replicas
- recreate the submirrors and reattach them to the respective mirrors
This is the current /etc/vfstab:
bash-3.00# cat /etc/vfstab #device device mount FS fsck mount mount #to mount to fsck point type pass at boot options # fd - /dev/fd fd - no - /proc - /proc proc - no - /dev/md/dsk/d0 - - swap - no - /dev/md/dsk/d10 /dev/md/rdsk/d10 / ufs 1 no logging /dev/md/dsk/d30 /dev/md/rdsk/d30 /export/home ufs 2 yes logging /devices - /devices devfs - no - ctfs - /system/contract ctfs - no - objfs - /system/object objfs - no - swap - /tmp tmpfs - yes -
From here on I will use d0 and its submirrors as an example. d0 consists of d1 and d2. d2 is on the failed disk.
d0: Mirror Submirror 0: d1 State: Okay Submirror 1: d2 State: Needs maintenance Pass: 1 Read option: roundrobin (default) Write option: parallel (default) Size: 45753093 blocks (21 GB) d1: Submirror of d0 State: Okay Size: 45753093 blocks (21 GB) Stripe 0: Device Start Block Dbase State Reloc Hot Spare c1t0d0s0 0 No Okay Yes d2: Submirror of d0 State: Unavailable Size: 45753093 blocks (21 GB) Stripe 0: Device Start Block Dbase State Reloc Hot Spare c1t1d0s0 0 No - Yes
First we detach d2. The same has to be repeated for d32 and d12:
bash-3.00# metadetach -f d0 d2 d0: submirror d2 is detached
We need to clear d2. Again, the same is repeated for d32 and d12:
bash-3.00# metaclear d2 d2: Concat/Stripe is cleared
Now we delete database replicas from the failed disk. It’s also very important to make sure we have at least half of state database replicas available before we start removing them from the failed disk. Here is Sun document that explains Majority Consensus Algorithm Solaris Volume Manager uses. You can determine number and location of the replicas using metadb -i command.
bash-3.00# metadb -d c1t1d0s7 ```> Now we can unconfigure the failed disk using _cfgadm_, replace it and configure the new disk: ```terminal bash-3.00# cfgadm -al Ap_Id Type Receptacle Occupant Condition c0 scsi-bus connected configured unknown c0::dsk/c0t0d0 disk connected configured unknown c0::dsk/c0t1d0 disk connected configured unknown c1 scsi-bus connected unconfigured unknown usb0/1 unknown empty unconfigured ok usb0/2 unknown empty unconfigured ok usb0/3 unknown empty unconfigured ok usb0/4 unknown empty unconfigured ok usb1/1 unknown empty unconfigured ok usb1/2 unknown empty unconfigured ok usb1/3 unknown empty unconfigured ok usb1/4 unknown empty unconfigured ok bash-3.00# cfgadm -c unconfigure c1::dsk/c1t1d bash-3.00# cfgadm -c configure c1::dsk/c1t1d0
Now we replicate VTOC from the good disk:
bash-3.00# prtvtoc /dev/rdsk/c1t0d0s2 | fmthard -s - /dev/rdsk/c1t1d0s2
Add database replicas to the new disk:
bash-3.00# metadb -a -c2 c1t1d0s7
Finally, we can recreate failed submirrors and attach them to their respective mirrors and let them sync up. Again, the same is applies for d32 and d12:
bash-3.00# metainit d2 1 1 c1t1d0s0 d2: Concat/Stripe is setup bash-3.00# metattach d0 d2 d0: submirror d2 is attached
Few notes: This setup contains total of 4 state database replicas. During a disk failure half of the replicas will be gone. If the server gets rebooted for whatever reason, it will not come up in multiuser mode. If you have less than half of the replicas, the system will panic. For more info on all that check out Solaris Volume Manager Administration Guide.
When using cfgadm to unconfigure disk, there can be no resources using that disk. Otherwise, unconfigure will fail. Quite possibly swap metadevice is set to be dedicated dump device. To view or change dedicated dump device settings use dumpadm command.