A while ago, I had complained:
> Among the (currently) 1170 full ULTRIUM4C tapes around here,
> with a wide variety of data, I see anything between "526.1 G" and "6.1 T".
>
> What I don't like: 20 % of the tapes are shown with a capacity of < 800 MB,
> but only 3.5 % with 1.6 TB or more. This seem
Hi Wolfgang,
Just to be sure, isn't <800GB just because data is expired? See if you have
reclaimable space on the tape.
Regards,
Maurice
2010/12/9 Wolfgang J Moeller
> Among the (currently) 1170 full ULTRIUM4C tapes around here,
> with a wide variety of data, I see anything between "526.1 G" a
6 PM
To: ADSM-L@VM.MARIST.EDU
Subject: Re: [ADSM-L] ULTRIUM4C but not 1.6TB
On Dec 9, 2010, at 12:26 PM, Scott McCambly wrote:
> ...
>
> I always assumed that the hardware compression mechanism would have
> something equivalent to "CompressAlways=NO" and detect already
> comp
Another consideration is that tape and disk sales people cleverly use
base 10, where 1K=1000, instead of what us geeks use where 1K=1024. So a
"800GB native capacity" LTO4 tape holds only 800,000,000,000 bytes,
which is less than 800GB. You lose 2.4% right there in salesman's tricky
fast talking.
On Dec 9, 2010, at 12:26 PM, Scott McCambly wrote:
> ...
>
> I always assumed that the hardware compression mechanism would have
> something equivalent to "CompressAlways=NO" and detect already
> compressed data in its input buffer, however we backup a number of
> already compressed file formats
nopsys.com]
Sent: Thursday, December 09, 2010 11:26 AM
To: ADSM-L@VM.MARIST.EDU
Subject: Re: [ADSM-L] ULTRIUM4C but not 1.6TB
This is related to a similar question I have been investigating on 3592
media: Why would you ever get less than the native capacity of a
tape?
Does writing compressed data to
This is related to a similar question I have been investigating on 3592
media: Why would you ever get less than the native capacity of a
tape?
Does writing compressed data to tape with hardware compression enabled
result in the data expanding?
I always assumed that the hardware compression mec
If a LTO4 tape holds more than 800GB compression is on.
At our place, file data only has a 1.1:1 compression while Oracle data and
mail is 2.5:1. Overall it is 2:1.
Hans Chr.
On Thu, Dec 9, 2010 at 9:18 AM, Mehdi Salehi wrote:
> Hi,
> Drives are LTO4, devclass is ULTRIUM4C, but all "Full" vol
Among the (currently) 1170 full ULTRIUM4C tapes around here,
with a wide variety of data, I see anything between "526.1 G" and "6.1 T".
What I don't like: 20 % of the tapes are shown with a capacity of < 800 MB,
but only 3.5 % with 1.6 TB or more. This seemed to be different with LTO3 -
unfortunat
On Dec 9, 2010, at 3:18 AM, Mehdi Salehi wrote:
> Hi,
> Drives are LTO4, devclass is ULTRIUM4C, but all "Full" volumes are between
> 800GB to 1TB. Is it normal? It seems TSM does not use compression.
The physical capacity of Ultrium 4 is 800 GB, so compression is obviously
happening. Some data
No compression before data gets to the drive. I will check with other kinds
of data.
Thank you.
ver 2TB on fileserver type data.
Steven
Mehdi Salehi
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09/12/2010 08:19
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[ADSM-L] ULTRIUM4C but not 1.6TB
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Hi,
Drives are LTO4, devclass is ULTRIUM4C, but all "Full" volumes are between
800GB to 1TB. Is it normal? It seems TSM does not use compression.
Mehdi
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