smitty mksysb backup is so long
byro...@neweb.com.tw
i am trying to do a system backup by "smitty mksysb"
but this jobs is stop in 92% so long ....
than i kill the process
i check error report is nothing
please help me .Thanks!!
Jason
The time of mksysb depends on your system hardware and the amount of data in
your rootvg. You may use df to have a check on the filesystem space, such as
/tmp, to see any abnormal change there during mksysb.
Jason
<byro...@neweb.com.tw> wrote in message
news:a6190beb.03080...@posting.google.com...
Steve Greatbanks
Make sure the block size of the tape device is set to 0?
Malcolm Preen
Are you sure ???
block size of 0 means variable block size....
Have you ever tried to restore a tape created with a block size of 0... ?
I've experienced restores taking 10 times as long to restore as they
originally took to backup.
I only ever use block size 0 when I am unable to read the tape (ie the
supplier has failed to specify the block size or format in which the data
is written).
It is IMHO much better to specify an actual block size... but the block
size required depends upon a number of things;
- what data you are backing up
- what type of tape device you are using
Going back to the original question - what we need to know is what is being
backed up... could it be that mksysb is backing up a large file
(database?).
It is possible (-v flag) to list each file as it is backed up... this
should give a clue.
But it would also assist if you specify the version of AIX, the model of
the machine and the model of the tape device.
Malcolm
--
Malcolm - Great Britain Old Timers #32 - 19/Apr/2002 GB 5 HC Paris 4
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Steve Greatbanks
"Malcolm Preen" <so...@spamcop.net> wrote in message
news:38tuivgvsr1t2tqpb...@4ax.com...
> On Mon, 4 Aug 2003 18:09:14 +1000, "Steve Greatbanks"
> <steve_gr...@hotmail.com> wrote:
> ><byro...@neweb.com.tw> wrote in message
> >news:a6190beb.03080...@posting.google.com...
> >> hi everyone
> >> i am trying to do a system backup by "smitty mksysb"
> >> but this jobs is stop in 92% so long ....
> >> than i kill the process
> >> i check error report is nothing
> >> please help me .Thanks!!
> >
> >Make sure the block size of the tape device is set to 0?
>
> Are you sure ???
Yep.
> block size of 0 means variable block size....
Yes. And then depends on the app to send a sensible block size. IIRC, the
default block size for most tape devices after cfgmgr creates the device
instance is 0 (certainly the case with LTO as I've just checked). Never had
an issue with block size of 0 and DLT or LTO using sysback or mksysb or
savevg or tar (or backup or pax, or cpio).
> Have you ever tried to restore a tape created with a block size of 0... ?
I hope that was not intended to be as patronising as it sounds!
> I've experienced restores taking 10 times as long to restore as they
> originally took to backup.
Never had that occur. What hardware and what backup utility?
Malcolm Preen
<steve_gr...@hotmail.com> wrote:
>> block size of 0 means variable block size....
>
>Yes. And then depends on the app to send a sensible block size. IIRC, the
>default block size for most tape devices after cfgmgr creates the device
>instance is 0 (certainly the case with LTO as I've just checked). Never had
>an issue with block size of 0 and DLT or LTO using sysback or mksysb or
>savevg or tar (or backup or pax, or cpio).
My experience has mainly been with older devices, 8mm and 4mm.
The 8mm 5.0Gb device which I have access to immediately has a default
block_size of 1024.
>> Have you ever tried to restore a tape created with a block size of 0... ?
>
>I hope that was not intended to be as patronising as it sounds!
It was a question... my experience obviously differs from yours.
>> I've experienced restores taking 10 times as long to restore as they
>> originally took to backup.
>
>Never had that occur. What hardware and what backup utility?
mksysb, older model RS6000s and 8mm and 4mm tape devices.
I'm currently running AIX 5.2 with an 8mm 5.0Gb device. I'll run some tests
and report back with the results...
I'm suspecting that it is something that is a problem with the "older"
devices, but not a problem with the newer ones....
Malcolm Preen
wrote:
>I'm currently running AIX 5.2 with an 8mm 5.0Gb device. I'll run some tests
>and report back with the results...
>
>I'm suspecting that it is something that is a problem with the "older"
>devices, but not a problem with the newer ones....
Hmm... OK, yesterday I ran a two mksysbs on my 7043-150 running AIX 5.2 to
my 5.0Gb 8mm Exabyte device, one with block_size=0 and one with
block_size=1024
Both backups took a fraction under 90 minutes to complete...
So, I tried to restore the last file on each tape (./websm.log).
Each restore took slightly over 60 mins.
So, I've not proved anything here... maybe the problem was only on 4mm
devices ? Or maybe it (if it existed) has been fixed in 5.2...
I'll try and locate a local machine with a 4mm tape device, and try to
reproduce the problem...