_____________________________________________________________________
Robert P. McGraw, Jr.
Manager, Computer System EMAIL: rmcgraw AT purdue DOT edu
Purdue University ROOM: MATH-807
Department of Mathematics PHONE: (765) 494-6055
150 N. University Street FAX: (419) 821-0540
West Lafayette, IN 47907-2067
> -----Original Message-----
> From: Paul Bijnens [mailto:paul.bijnens AT xplanation DOT com]
> Sent: Wednesday, August 02, 2006 11:37 AM
> To: McGraw, Robert P.
> Cc: amanda List
> Subject: Re: tapetype question
>
>
> On 2006-08-02 15:08, McGraw, Robert P. wrote:
> > ./sbin/amtapetype -o -t LTO2HWC -e 200g -f /dev/rmt/1n
> >
> > Writing 2048 Mbyte compresseable data: 38 sec
> > Writing 2048 Mbyte uncompresseable data: 76 sec
> > WARNING: Tape drive has hardware compression enabled
> > Estimated time to write 2 * 204800 Mbyte: 15200 sec = 4 h 13 min
> > wrote 6422528 32Kb blocks in 98 files in 7358 seconds (short write)
> > wrote 6455296 32Kb blocks in 197 files in 7737 seconds (short write)
> > define tapetype LTO2HWC {
> > comment "just produced by tapetype prog (hardware compression on)"
> > length 201216 mbytes
> > filemark 0 kbytes
> > speed 27315 kps
> > }
> >
> > I am in the process of trying to find out how to turn off hardware
> > compressing for the Solaris 10 OS.
>
>
> I hope you did understand that turning off hardware compression for
> LTO tape drives is not so important as for most other tape drives.
[McGraw, Robert P.]
Yes I did.
>
> So why doing the effort, while you can use both hard- and software
> compression, and not suffer from the bad side effect (expanding data
> and loosing capacity) that most other tape drives have.
[McGraw, Robert P.]
Inquiring minds want to know.
I have a request in to Sun support to try and find the answer.
>
> As Joshua, I have hardware compression turned ON for my LTO2 drive,
> so that a few DLE's on slow hosts, where I cannot afford software
> compression, still benefit from the hardware compression and my
> tapes can hold more than 100% data now and then.
[McGraw, Robert P.]
I am planning to leave it as is. I do not software compress at this time.
Why take up the CPU cycles to software compress your data if it is going to
be compressed on hardware?
Thanks
Robert
>
>
> --
> Paul Bijnens, xplanation Technology Services Tel +32 16 397.511
> Technologielaan 21 bus 2, B-3001 Leuven, BELGIUM Fax +32 16 397.512
> http://www.xplanation.com/ email: Paul.Bijnens AT xplanation DOT com
> ***********************************************************************
> * I think I've got the hang of it now: exit, ^D, ^C, ^\, ^Z, ^Q, ^^, *
> * F6, quit, ZZ, :q, :q!, M-Z, ^X^C, logoff, logout, close, bye, /bye, *
> * stop, end, F3, ~., ^]c, +++ ATH, disconnect, halt, abort, hangup, *
> * PF4, F20, ^X^X, :D::D, KJOB, F14-f-e, F8-e, kill -1 $$, shutdown, *
> * init 0, kill -9 1, Alt-F4, Ctrl-Alt-Del, AltGr-NumLock, Stop-A, ... *
> * ... "Are you sure?" ... YES ... Phew ... I'm out *
> ***********************************************************************
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