In my opinion, this is Micro-managing something to death that doesn't
need it... 
The effort expended in doing this will not be worth the minor benefits
gained...
We have IBM LTO2 drives and use Dell branded tapes (I'm sure they're not
made by Dell, just re-branded from a reputable manufacturer like
quantum, etc. Dell seems to re-brand a lot of stuff, but most if it
seems to be pretty good quality). I have also noticed the range of tape
capacity can vary greatly, but I think this is more due to the type of
data written to them and whether it is compressed before it reaches the
tape drive. If it's compressed first, you end up with a higher data
density and therefore, more of it fits on a tape. I don't think it has
anything to do with the tape quality. Data already on a tape has no
'quality' per say, the only thing that matters is: can the tape be read
by Networker when doing a restore ? If the answer is yes, that's all you
can hope for, otherwise it could be a bad tape and needs to be pitched
because it's not worth the risk of recycling it and not being able to
depend on it for a restore if needed. LTO2 tapes are supposed to have a
limit of 50 cycles (each label operation begins a new cycle). We have
not reached that limit yet with any of our tapes so far (we have approx
1400), but if we begin to get tape errors, we may replace them with new
tapes when that time comes...

> -----Original Message-----
> From: EMC NetWorker discussion 
> [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On Behalf Of kurianv
> Sent: Tuesday, August 05, 2008 5:40 AM
> To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
> Subject: [Networker] Quality of the tapes
> 
> Hi everyone,
> 
> I am basically new to networker. But i would like to ask a 
> question about the quality of the data in the tapes or the 
> tapes itself.
> 
> The tapes what I am using is HP Super DLT Tapes with capacity 
> 320 GB. I was actually going through the inventory and i 
> found out that for some tapes the volume written was around 
> 120- 130  GB where as for several other tapes it varied 
> between 200-400 GB. What I want to ask is that, I think there 
> are 2 types of data being written , i.e. compressed as well 
> as uncompressed. So is the tapes showing 120-140 GB having 
> good quality.
> Because what we want is to reduce the total number of tapes 
> being backed up for say weekly backups. So in order to reduce 
> we will have to scrap of the bad quality tapes. So can u 
> suggests how can i know the quality of the tapes from 
> networker or even if there is no method , can u suggests what 
> threshold value i should put for this to scrap off.
> 
> Rgds,
> Kurian
> 
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