08-07-2011 01:50 AM
Hello again,
We use a mixture of LTO 3 and LTO4 tapes.
We read in the last six characters for the media ID. At the end of the barcode there is an L4\L3 indicating the tape type.
Is there really a need for this other than to identify the tape type? Would it affect the system if new barcodes had these characters replaced by numbers?
Cheers,
Al.
08-07-2011 03:27 AM
It is not a requirement I would say. It's up to how you want to manage them.
For me, I most likely would use different storage units for LTO3 & LTO4, but that does not mean I need L3/L4 at the back of the mediaID. If there is a unique alphabet for those barcodes I order between the LTO, I may just use the first 6 and omit the L3/L4.
Using only 4 characters plus the L3/L4 may have a problem if your barcode is not unique. For example, the barcode you order could have these:
BA0011L3
CA0011L3
the mediaID generation will detect a duplicate here!
Using the first 6 will be a better option in this case, but you gotta make sure you don't have
BA0011L3
BA0011L4
:)
08-07-2011 06:41 AM
I agree - it is not a requirement, merely the default. Most customers prefer the 1st 6, but that decision is normally made right from the start.
As long as the density types can be identified using barcode rules the 1st 6 is fine.
It might become quite a headace if you decide to change if using the last 6 chars has been in place for some time. All existing database entries as well as tape headers will be written with last 6. Changing now will mean you will have to delete all media as they expire (deassigned) so that the new Media Id Generation rule can be applied when you inventory. You will then have to manually label all of those tapes to prevent media from being frozen the 1st time it needs to be overwritten (... expected 000001 in drive xxxx, found 0001L3 ....).
08-08-2011 02:36 AM
The tapes must end in L1, L2, L3, L4 or L5.
In some libraries if this isn’t done it won’t read the tape.
Also anything above LTO4 must have the correct ending - The last company I worked for had LTO4 tapes with barcodes ending in L1 - this were rejected by the library as being incompatible.
Use the 1st 6 - its so much better.
08-08-2011 10:02 AM
If you look at the physical barcode you see that the L# is part of the barcode by default and is required for the library to know what type of tape it is.
The only thing you can change is if you see the first 6 or last 6 for the media ID.
you Barcode can see how all 8, but your media ID can be the first 6.
08-08-2011 10:21 AM
it is also possible to amend your library to only "present" certain characters to NetBackup - e.g. 123456L3 could be presented as a six-digit 123456 omitting the L3 suffix.
08-09-2011 03:28 AM
Hi Mark
This was my main concern and I was always curious about this.
At one of our sites on a different NBU domain some tapes end with an L2, and are used in an LTO3 tape library with no problem at all.
I was never sure if this would cause a problem.
Cheers,
Al
08-09-2011 03:42 AM
- don't forget LTO drives can read & write one generation back & read only two generations back.
e.g.
LTO3 drives can read & write LTO2 (L2 suffix if labelled correctly) & read only LTO1 (L1)
LTO4 drives can read & write LTO3 (L3) & read only LTO2 (L2) but not compatible with LTO1 (L1)
08-09-2011 04:08 AM
Hi Marianne
The thing is, I wanted to use the first 3 characters to represent the site specific location code. Then set the barcode rule to import tapes into separate volume pools based on site location code and set the media ID generation rule to use the first 6 characters.
However, doing it this way would only leave us with 999 tapes per site location which wouldn’t be enough to last that long. So then I thought I’d keep the idea with using the site specific code and barcode rule but instead set the media id generation rule to read the last 6, (but not get barcodes with the L3 or L4 etc) therefore giving us more available tapes seeing as we’d have 5 characters to play with. I think I’ll be best moving away from the 3 letter site code idea.
08-09-2011 04:27 AM
Ah yes, but I think what happened is that they had run out of LTO3 labels and used an LTO2 label on an LTO3 tape.
Would the library treat this tape as though it was an LTO2 tape even though it was actually and LTO3? :)
08-10-2011 03:08 AM
Hi J
Just remember some people have software to print their own labels - why they do it is beyond me when its so cheap to buy pre-labelled tapes.
Algon - I think that tape will be treated as LTO2. Depends on the library. HPs don’t seem to care, Quantum / Adic do.
Regards,
Mark
08-10-2011 07:35 AM
Some people have a need to be able to easily see or separate tapes.
Say for example catalog tapes as they are special and cannot be used as normal tapes once used for catalog - and if you have to do a recovery you can easily see in a batch of tapes which ones are the catalogs.
So asking for labels that start with C and are all of one color would be a way to see that. Having different NB domains or more than one robot could also be a reason for labels that can be easily identified.
So when ordering tape just tell them what you labels you want (as all tapes come with a label anyway - just as easy to get some special ones if you have the need) I would never buy the software to make them to easy to just get them when buying tapes.
And some people mico-manage their tapes by having lots of volume pools - like one for Monday and Tuesday..... on one for monthly.... with special barcodes they can setup barcode rules as to which volume pool they go into.