HP XP Continuous Access Software - Manual (Page 203)

Splitting Continuous Access XP Journal volume pairs
When splitting a Continuous Access XP Journal volume pair, you can choose either offline or online
backup. With offline backup, you can split the pair by unmounting the P-VOL. With online backup, you
can split the pair by temporarily saving updates to a file system without unmounting the P-VOL.
During offline backup, a Continuous Access XP Journal volume pair is split after completely stopping
access from clients by deleting CIFS/NFS shares. Since I/O errors are reported to the application if
CIFS/NFS shares are deleted while the application writes data in the P-VOL or if the application tries to
write data in the P-VOL after deleting CIFS/NFS shares, it can be distinguished by the application data
reflected in the Continuous Access XP Journal volume pair. Therefore, it is applicable to most applications.
During online backup, however, a Continuous Access XP Journal volume pair is split without deleting
CIFS/NFS shares. Since I/O errors are not reported to the application when writing data to the P-VOL, it
cannot be distinguished by which time data is reflected in the S-VOL. For this reason, it is applicable only
to the application that can identify where data was updated with a journal file, and so on.
Offline backup
To split the Continuous Access XP Journal volume pair with offline backup:
1. At the primary site, stop the program that accesses the P-VOL.
2. At the primary site, delete NFS/CIFS shares in the P-VOL using the enas_nfsdelete and enas_cifsdelete
commands in NAS Blade Manager. Unmount the P-VOL using the enas_fsumount command.
3. At the primary site, prevent NAS Sync Image from performing operations on the P-VOL:
sudo horc_pvol_freeze -f Source file system name
4. At the primary site, split the Continuous Access XP Journal volume pair.
sudo pairsplit {-g group-name|-d volume-name} -rw
5. At the primary site, verify that the Continuous Access XP Journal volume pair has been split.
sudo pairvolchk {-g group-name|-d volume-name}
NOTE:
You can also use the pairevtwait command, which waits for the pair to be split (PSUS).
pairvolchk: Volstat is P-VOL.[status = COPY] => Splitting
pairvolchk: Volstat is P-VOL.[status = PSUS] => Split completes
6. At the primary site, enable operations from NAS Sync Image on the P-VOL.
sudo horc_pvol_unfreeze -f Source file system name
7. At the primary site, mount the P-VOL using the enas_fsmount command in NAS Blade Manager, and
create CIFS/NFS shares using the enas_nfscreate and enas_cifscreate commands.
8. At the primary site, restart the program that accesses the P-VOL.
9. At the secondary site, connect the target file system to the NAS package.
• Non-LVM:
sudo horc_svol_import -f Target-file-system-name -d Device-file-number
• LVM:
sudo horc_svol_vmimport -f Target-file-system-name -d Device-file-number, ...
10. At the secondary site, mount the S-VOL using the enas_fsmount command. Create a shared
directory using the enas_dircreate command, or change the attributes of a shared directory using
the enas_diredit command. Create CIFS/NFS shares using the enas_nfscreate and nas_cifscreate
commands.
Continuous Access XP Journal user guide 203