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
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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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
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
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
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
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
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
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.
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
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
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
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