I totally agree with what Don is saying, it makes much more
sense to change the density of the new drives to match the old drives and
change any new LTO4 media that’s been put in to match as well.
Not only is there probably more to change if you’re
changing all of the old media to the new media type, but each and every
fragment in the image catalog lists the media type that the fragment is on.
I seem to recall an issue in the lab once when the image was written to one
media type, the media type was changed and I tried a restore. Personally,
I wouldn’t change the media type of an assigned media without a lot of testing.
As it’s been said over and over on this list, the
difference between hcart, hcart2 and hcart3 is nothing more than a unique name
for an hcart type density. Just because it’s an LTO1, 2 or 4 doesn’t
mean you can’t use hcart3 for it.
However, I believe you’re still going to need to modify
the Media Type Mappings. By default, when NetBackup is told by ACSLS that
the tape is LTO_400G (an ACSLS media type) it will map it to an hcart3 media
type within NetBackup. LTO_800G will map to hcart.
If your LTO4 drive was configured by NetBackup as hcart and you
change it to hcart3 along with your new LTO4 tapes, new LTO4 tapes will be
passing LTO_800G media type from ACSLS to NetBackup which maps to hcart even
though either yourself or the Barcode Rules told NetBackup to configure the
tapes as hcart3. NetBackup will complain about this during an inventory.
In this case, you’ll need to change the Media Type Mapping of LTO_800G from
hcart to hcart3.
The change in the GUI is temporary. You’ll have to
change in vm.conf to be permanent. Please see Media Type Mappings in NetBackup
Admin Guide for more information on this.
From:
veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Don
Peterson
Sent: Thursday, July 02, 2009 4:08 PM
To: VERITAS-BU AT MAILMAN.ENG.AUBURN DOT EDU
Subject: [Veritas-bu] mounting lto3 tapes to lto4
You said, “we're planning on replacing
our LTO3 drives with LTO4s entirely but want to utilize the many LTO3 tapes
that we still have. The problem that we have is that Netbackup sees these
tapes as different media types/densities because ACSLS provides it that way and
therefore i can't mount "hcart3" tapes into an "hcart" type
storage unit in Netbackup. Has anyone experienced this and know of a
workaround?”
Migrating to a new generation
drive technology that provides R/W compatibility, but CAN’T write to
previous-generation
media at the higher density
The following steps should
be taken to implement this type of migration with NetBackup software. A typical example of this
would be migrating from LTO2 to LTO3.
1) Replace all of the old
drives with new drives. Depending on how the NetBackup device configuration wizard automatically
configures the new drives, or how they may have been manually configured, the drives may
need to be reconfigured to match the drive type of the old drives. This is necessary so
that the new drives can read the existing media. Changing the drive type can be accomplished by
right clicking on the drive in the Media and Device Management GUI. NetBackup software
will automatically configure LTO drives as HCART, LTO2 drives as HCART2, LTO3 drives
as HCART3, and LTO4 drives as HCART. In this case, if migrating to LTO3 drives, the LTO3
drives would need to be reconfigured as HCART2.
2) Define storage units for the new
drives and add backup policies to use those drives.
3) The new drives should
provide higher capacity and speeds than the old drives. However, since the new drives cannot write to
existing media at the higher density, you may no longer want to use that media for backups.
If you DO want to continue to use existing media for doing backups, then no other steps
are required. When using both types of media for backups, backups will potentially take
longer due to the lower
density of the older media and you may span backups across dissimilar media.
4) If you no longer want to
use existing media for backups, you
should freeze the tapes, so NetBackup can only read from them. After all images on a piece of media expire, it becomes
unusable. You can use the bpmedialist command to determine which media have become expired and
frozen.
5) Once the media has
expired, it should be removed from the NetBackup image and media catalogs by using the
bpexpdate command. The following command can
be used to remove a single
piece of media (media_id) from the catalogs:
/usr/openv/netbackup/bin/admincmd/bpexpdate
-m media_id
6) Next, the physical media
should be removed from the library. This can be accomplished by ejecting the media.
7) Finally, use the NetBackup Administration
Console to delete the volume from the
NetBackup volume database.
Don
Peterson
Product
Manager, NetBackup
Information
Management Group
Symantec
Corporation