zfs discuss - Oct 2010 - moving newly created pool to alternate host

Hi,

If have below kind of configuration (as an example):

c1t1d1 and c2t2d2 are two LUNs visible (un masked) to both host1 and host2. 

Created a pool mypool as below

   zpool create mypool mirror c1t1d1  c2t2d2

Now I did zpool split
  zpool split mypool mypool_snap

Once i run zpool split, is there a way I can move/visible newly created
mypool_snap to other host i.e host2 ??
so that I can able to access all file systems and files in read only mode for
backup?


Thanks & Regards,
sridhar.
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This message posted from opensolaris.org

Hi Sridhar,

After a zpool split operation, you can access the newly created
pool by using the zpool import command.

If the LUNs from mypool are available on host1 and host2, you
should be able to import mypool_snap from host2. After mypool_snap
is imported, it will be available for backups, but not in read-only
mode.

It is important that data from these pools is not accessed from two
the different hosts at the same.

An upcoming feature is a read-only import that might be helpful
in your environment.

Thanks,

Cindy

On 10/05/10 07:41, sridhar surampudi wrote:
> Hi,
> 
> If have below kind of configuration (as an example):
> 
> c1t1d1 and c2t2d2 are two LUNs visible (un masked) to both host1 and host2.
> 
> Created a pool mypool as below
> 
>    zpool create mypool mirror c1t1d1  c2t2d2
> 
> Now I did zpool split
>   zpool split mypool mypool_snap
> 
> Once i run zpool split, is there a way I can move/visible newly created
mypool_snap to other host i.e host2 ??
> so that I can able to access all file systems and files in read only mode
for backup?
> 
> 
> Thanks & Regards,
> sridhar.

Hi Cindys,

Thanks for your mail.  I have some further queries here based on your answer.
Once zfs split creates new pool (as per below example it is mypool_snap) can I
access mypool_snap just by importing on the same host Host1 ??


what is the current access method of newly created  mypool_snap ? is it
read-write or read only ?
If it is read-write is there a way I can make it read only so that backup
application cannot misuse.

Also I want (or going to use ) mypool_snap as read only on alternate host i.e.
host2.  Could you please let me know what all steps I need to take on host1 and
then on host2 once zpool split is done.

I can guess as after zpool split, mypool_snap is not visible to host1. Once
needs to import explicitly. Instead of importing on same host i.e. host1 can i
go to host2 where split node devices are visible and directly run zpool import
mypool_snap which will be further used as read only for backup ??

Could you please provide more details.
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This message posted from opensolaris.org

Hi Sridhar,

Most of the answers to your questions are yes.

If I have a mirrored pool mypool, like this:

# zpool status mypool
   pool: mypool
  state: ONLINE
  scan: none requested
config:

         NAME        STATE     READ WRITE CKSUM
         mypool      ONLINE       0     0     0
           mirror-0  ONLINE       0     0     0
             c3t1d0  ONLINE       0     0     0
             c3t2d0  ONLINE       0     0     0

errors: No known data errors

and I split it like this:

# zpool split mypool mypool_snap
# zpool status
   pool: mypool
  state: ONLINE
  scan: none requested
config:

         NAME        STATE     READ WRITE CKSUM
         mypool      ONLINE       0     0     0
           c3t1d0    ONLINE       0     0     0

Only mypool is currently imported. The new pool mypool_snap is exported
by default. So, you can either import it on host1 or host2 if the LUNs
are available on both systems.

# zpool import mypool_snap
# zpool status mypool mypool_snap
   pool: mypool
  state: ONLINE
  scan: none requested
config:

         NAME        STATE     READ WRITE CKSUM
         mypool      ONLINE       0     0     0
           c3t1d0    ONLINE       0     0     0

errors: No known data errors

   pool: mypool_snap
  state: ONLINE
  scan: none requested
config:

         NAME        STATE     READ WRITE CKSUM
         mypool_snap  ONLINE      0     0     0
           c3t2d0    ONLINE       0     0     0

errors: No known data errors


In current Solaris releases, only ZFS file systems are mounted
read-only. The ability to import a pool read-only is available with
CR 6720531.

If you import mypool_snap on host2, it will not be available or
visible on host1.

Thanks,

Cindy







On 10/07/10 15:36, sridhar surampudi wrote:
> Hi Cindys,
> 
> Thanks for your mail.  I have some further queries here based on your
answer.
> Once zfs split creates new pool (as per below example it is mypool_snap)
can I access mypool_snap just by importing on the same host Host1 ??
> 
> 
> what is the current access method of newly created  mypool_snap ? is it
read-write or read only ?
> If it is read-write is there a way I can make it read only so that backup
application cannot misuse.
> 
> Also I want (or going to use ) mypool_snap as read only on alternate host
i.e. host2.  Could you please let me know what all steps I need to take on host1
and then on host2 once zpool split is done.
> 
> I can guess as after zpool split, mypool_snap is not visible to host1. Once
needs to import explicitly. Instead of importing on same host i.e. host1 can i
go to host2 where split node devices are visible and directly run zpool import
mypool_snap which will be further used as read only for backup ??
> 
> Could you please provide more details.

Hi Cindys,

Thank you for step by step explanation and it is quite clear now.

Regards,
sridhar.
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