Thanks you



On Mon, Jul 12, 2010 at 6:09 AM, J. Pohlmann <jpohlmann AT shaw DOT ca> wrote:

> In many installations it's a close to meaningless number. For empty tapes,
> it's the estimated capacity of the tape multiplied by maxscratch. Then as
> tapes become full, the actual number of bytes written will modify the
> estimated capacity value. The actual bytes written depends on
> compressibility of the data.  The reason why in most of my installations it
> is a meaningless number is that tape libraries are managed by the number of
> scratch tapes available. I generally suggest that there should be about 10%
> scratch tapes in a tape library or at least five (five is also the
> threshold
> value for attention grabbers in the TSM v5 Operational Reporting Facility).
> Tape storage pools are then not restricted by the number of scratch tapes
> that may be assigned. Very often maxscratch is set to 10000 or some such
> number. You will often find large maxscratch values also in
> server-to-server
> virtual volume environments where the maximum capacity in most cases is set
> to be significantly smaller than the capacity of, for example LTO3 or LTO4
> tapes.
>
> Note that for device class disk storage pools the estimated capacity is the
> actual capacity.
>
> Joerg Pohlmann
> 250-585-3711
>
> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf 
> Of
> Mehdi Salehi
> Sent: Friday, July 09, 2010 08:06
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: [ADSM-L] tape stg capacity
>
> Hi,
> How is tape storage pool "estimated capacity" calculated? I see different
> values for similar storage pools of the same devclass and maxscratch.
>
> Thanks
>