| Hello,
I have a partner who is getting an advfs "Next free page has no free mcell"
error after attempting to restore (using his own app) to the rootvol. Here is
mail from him describing what he believes his problem stems from. He also has a
couple of questions related to rootvol. I'd appreciate any feedback.
Thanks.
Pat Bryant
Software Partner Engineering
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We have a system backup/restore product which we want to support LSM.
The product lets users backup/restore raw disks and in the case of LSM
we backup/restore LSM raw files (e.g. /dev/rvol/rootdg/rootvol) to/from
tapes. My questions involve a disaster scenario in which an LSM
bootable disk (assume no mirroring exists unfortunately) crashed and
we need to restore the system back from the tapes. There are two
typical ways for people to perform disaster recovery:
1. Reformat the crashed disk and install OS and LSM to it, then perform
recovery tasks.
I tried this method to restore my original /dev/rvol/rootdg/rootvol
back. However, my files were not restored even though our product could
successfully write() the data from tape to /dev/rvol/rootdg/rootvol.
My question is, does LSM allow such writes to the rootvol while
it is mounted to / file system?
p.s. my rootvol was encapsulated from AdvFS so I have a link:
/etc/fdmns/root_domain/rootvol ---> /dev/vol/rootdg/rootvol
2. Install OS on another disk and restore data to the original disk.
Is it possible to use this method to restore the LSM rootvol?
The rootvol has the "root" usage-type. Does LSM allow you to create
a volume with "root" type? I tried to do this using volassist
utility to create a volume on the original disk, and unfortunately
it core dumped.
|
| Jay,
I found some information regarding restoring of an LSM root disk. It is
from our Customer Support Center and is in regard to a customer having problems
when using vdump and vrestore on an LSM disk to provide for disaster recovery.
Here is verbatim a response to the customer who was unable to make a bootable
copy of the root parition of an LSM disk using vdump.
"The problem with your new bootable disk is that the original was LSM
encapsulated and the OS expects it (from other traits in the filesystem) to
be a fully LSM-compliant structure. LSM creates a private data area on the
original disk which contains more information for dealing with the
partitioning. A straight vdump/vrestore can't see that external information.
There is no quick or easy way to restore the LSM private data; your best
bet would be to regularly use volprint with the "-m" parameter and store it
with your backups (and in hardcopy somewhere!) so that you can feed it back
to volmake in the aftermath of a catastrophic crash and recreate the LSM
layout. (See the man pages for more detail, or the LSM book.)
If you're just trying to `jumpstart' to operative running after a crash,
you can restore to the disk, after making sure its partitioned, etc,
without even involving LSM immediately. Once you're up and running, you
can encapsulate root and swap and rebuild the rest, but if your user/run
data is on LSM partitions, at some point it'll have to be brought up."
Does this help at all? Based on this, do you have further questions?
Pat Bryant
|