ADSM-L

Re: tape become full in 21 percent.

2002-11-25 10:12:09
Subject: Re: tape become full in 21 percent.
From: Salak Juraj <j.salak AT ASAMER DOT AT>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Mon, 25 Nov 2002 16:10:28 +0100
> Reclamation precess (which is hard, close to
> impossible, to do on
> single drive)

Just my two cents:
Reclamation on single drive is OK
as long as you can offer enough disk space for reclamation process
to "buffer" data migrated.
This would mean 30++ GB in this case.

regards
Juraj Salak



> -----Original Message-----
> From: Zlatko Krastev [mailto:acit AT ATTGLOBAL DOT NET]
> Sent: Monday, November 25, 2002 3:32 PM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: tape become full in 21 percent.
>
>
> Consider following scenario:
> 1. you backup say 40 GB
> 2. next day you backup 40 GB of which 35 GB updated - 35 GB
> from step 1
> expire.
> 3. perform step 2 for four days.
>
> The result you have 40 + 4x 40 GB = 200 GB written on tape.
> Tape reached
> the end and becomes "Full". At the same time you had 4x 35 GB = 140 GB
> expired. Thus you tape holds 200 - 140 = 60 GB (30%)
> real-data. The rest
> is gaps. Reclamation precess (which is hard, close to
> impossible, to do on
> single drive) can help.
>
> Zlatko Krastev
> IT Consultant
>
>
>
>
>
>
> Sudheer Kumar <sudheer AT COSMOS.DCMDS.CO DOT IN>
> Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
> 26.11.2002 14:22
> Please respond to "ADSM: Dist Stor Manager"
>
>
>         To:     ADSM-L AT VM.MARIST DOT EDU
>         cc:
>         Subject:        tape become full in 21 percent.
>
>
> Hi
>
> I am using LTO 3580 tape drive. but my tape capacity is 100/200GB but
> never got more than 31% utilization. When it reaches 25 to
> 31percent it
> become Full.Can anybody tell me what could be the reason.
>
> Regards
>
> Sudhir
>