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 seemed to be
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 moel...@gwdg.de
Among the (currently) 1170 full ULTRIUM4C tapes around here,
with a wide variety of data, I see anything
@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
compressed data in its input buffer, however we
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
on fileserver type data.
Steven
Mehdi Salehi ezzo...@gmail.com
Sent by: ADSM: Dist Stor Manager ADSM-L@VM.MARIST.EDU
09/12/2010 08:19
Please respond to
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To
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Subject
[ADSM-L] ULTRIUM4C but not 1.6TB
Caterpillar: Confidential Green
No compression before data gets to the drive. I will check with other kinds
of data.
Thank you.
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 is
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 -
unfortunately
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 ezzo...@gmail.com wrote:
Hi,
Drives are LTO4, devclass is ULTRIUM4C,
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
]
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 tape
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 and
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.
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