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Friday, November 22, 2013

Boot from SAN (Brocade HBA's)


Boot from SAN.

EMC TimeFinder Clone (Symclone)

1. Creating a new session.
#symclone -f <devices file> create -copy/-precopy -sid <symm id> -nop
If you use -copy copying blocks from source to target LUNS gets copied in the background  as soon as activate them.   If you use –precopy, copy will start immediately and won’t wait for activate to be run. Note : This will be full copy from source to target
2. Activating a previously created session.
#symclone -f <devices file> activate -sid <symm id> -consistent  -nop
As soon as session is activated block level copy starts if session is created with -copy option.
3. Query the session to find out how is copy going on. You would see status as “copy in progress” or “Copied”.
#symclone -f <devices file> query -sid <symm id> –nop
4. If copying is complete and you want to create a new session. before to that you’ve to Terminate the existing session.
  #symclone -f <devices file> terminate -sid <symm id> –nop
All the above steps does are full copy from source LUN to target LUN. If you don’t want to do full copy & copy the only changed tracks. symclone has that options too.

Differential Copy :

1.Create a first session with -diff option
#symclone –f <devices file> create  -copy/-precopy –diff –sid <symm id> –nop
Note : This session will be full copy too. only thing is subsequent copies can be created with recreate option & they’ll be just differential and fast.
2.   Activate the session.
#symclone -f <devices file> activate -sid <symm id> -consistent  -nop
3. for subsequent point in time clone creations. you don’t(shouldn’t) need to terminate the session. instead Recreate the same session using below and activate them using activate.
#symclone -f <devices file> recreate -sid <symm id> –nop
4. Activate it for start copying blocks. This should be fast.
#symclone -f <devices file> activate -sid <symm id> -consistent  -nop

Restoring or Reverse Cloning :

Incase if something happens to source LUNS. if you want to restore from target. you could do using following commands. you don’t have to flip the devices. you could use same device file.
#symclone -f <devices file> restore -sid <symm id> –nop
you don’t need to activate as restore will establish in opposite directions and automatically activates them to. when you query you should see the status as “Restore in Progress”. once restore is complete you would see “Restored”.
If you want to normal clone from source to target again after restore is complete. you need to Split the existing reverse clone session by using below command.
#symclone -f <devices file> split -sid <symm id> –nop
Now. you could go-ahead with recreate and activate for normal clones.

Format of the device file :
# SRC-LUN    TGT-LUN
   1300              1500

Info took from - gdesaboyina.wordpress.com and EMC docs