Shadow files on CKD (non-compressed) ?

[Mike Stramba]

Shadow files do not seem to work on non-compressed CKD

According to the manual they do ?

Or am I missing something (yet again ? )

Mike

[Gerhard Postpischil]

Post by Mike Stramba
Shadow files do not seem to work on non-compressed CKD
According to the manual they do ?
Or am I missing something (yet again ? )

Probably. I use shadow files on some of my volumes, all of which are
uncompressed (I don't want a job failing on lack of space needed to
expand). For example, all my SORT and work disks are shadowed, and the
batch file I use to start Hercules erases those.

Check spelling of file names, and make sure of the correct path and
directory names.

Gerhard Postpischil
Bradford, Vermont

[paoloG]

To tell the truth I too thought that shadow files were supported
only on compressed dasd (CCKD or CFBA);at least that's what Hercules manuals are saying.

So I tried to define a shadow file on a CKD DASD, and this is the Hercules message I get trying to create a shadow file:

sf+ 14d
HHCPN084E Device number 0:014D is not a cckd device

Regards

Paul

Post by Gerhard Postpischil

Post by Mike Stramba
Shadow files do not seem to work on non-compressed CKD
According to the manual they do ?
Or am I missing something (yet again ? )

Probably. I use shadow files on some of my volumes, all of which are
uncompressed (I don't want a job failing on lack of space needed to
expand). For example, all my SORT and work disks are shadowed, and the
batch file I use to start Hercules erases those.
Check spelling of file names, and make sure of the correct path and
directory names.
Gerhard Postpischil
Bradford, Vermont

[Mike Stramba]

Gerhard,

Are running on 'Nix or 'Doze ? (It *shouldn't matter ???)

If you issue an sfk <dev> on an uncompressed volume, what do you get ?

I get :

0110 3330 t3330-un ro sf=sh/t3330-un_
0120 3330 t3330.cckd ro sf=sh/t3330.cckd_

sfk 110
HHCPN084E Device number 0:0110 is not a cckd device

For a 3330 that I created with the -z option :

sfk 120
HHCCD210I size free nbr st reads writes l2reads hits switches
HHCCD212I --------------------------------------------------------------------
HHCCD213I [*] 4678 0% 0 0 0 0 0 0
HHCCD215I t3330.cckd
HHCCD216I [0] 3534 0% 0 ro 0 0 0
HHCCD217I sh/t333*.cckd_
HHCCD218I [1] 1144 0% 0 rw 0 0 0
Command ==>

Post by Gerhard Postpischil

Post by Mike Stramba
Shadow files do not seem to work on non-compressed CKD
According to the manual they do ?
Or am I missing something (yet again ? )

Probably. I use shadow files on some of my volumes, all of which are
uncompressed (I don't want a job failing on lack of space needed to
expand). For example, all my SORT and work disks are shadowed, and the
batch file I use to start Hercules erases those.
Check spelling of file names, and make sure of the correct path and
directory names.
Gerhard Postpischil
Bradford, Vermont

[Gerhard Postpischil]

Post by Mike Stramba
Are running on 'Nix or 'Doze ? (It *shouldn't matter ???)

I have it on Win XP3 and 7.

Post by Mike Stramba
If you issue an sfk <dev> on an uncompressed volume, what do you get ?

I do not use a separate command, but define the shadow file name on the
device definition. Hercules then creates the shadow file at start-up.

Gerhard Postpischil
Bradford, Vermont

[Mike Stramba]

Post by Gerhard Postpischil
I do not use a separate command, but define the shadow file name on the

device definition. Hercules then creates the shadow file at start-up.

I don't usually use that command either, but i's a way of verifying
whether the shadow file is working.

I only thought of using it, when I noticed the shadow file directory was empty.

Post by Gerhard Postpischil

Post by Mike Stramba
Are running on 'Nix or 'Doze ? (It *shouldn't matter ???)

I have it on Win XP3 and 7.

Post by Mike Stramba
If you issue an sfk <dev> on an uncompressed volume, what do you get ?

I do not use a separate command, but define the shadow file name on the
device definition. Hercules then creates the shadow file at start-up.
Gerhard Postpischil
Bradford, Vermont

["Fish" (David B. Trout)]

Post by Mike Stramba
Shadow files do not seem to work on non-compressed CKD

Correct.

Post by Mike Stramba
According to the manual they do ?

Then the manual is wrong. Where are you seeing this?

Post by Mike Stramba
Or am I missing something (yet again ? )

Probably. :)

Shadow files are only support on compressed dasd (CCKD and/or CFBA). They
are not support on regular uncompressed CKD format dasd. The CCKD (and
CFBA) emulated dasd file format is completely different.

If you wish to use shadow files your Hercules emulated dasd must be the
compressed variety (CCKD or CFBA). You can use the 'dasdcopy' utility to
convert your existing Hercules dasd from one format to the other via the
'-o' (output format) option. Use the '-z' or '-bz2' option to select which
your preferred compression algorithm.

If you wish to use shadow files but do not wish to incur the extra CPU
overhead involved in compressing and uncompressing track data, then simply
specify the '-0' (don't compress) option to disable any actual compression
from taking place. The resulting dasd file will still be in "compressed
format" (CCKD or CFBA), but no actual compression will take place. This
allows you to use shadow files without incurring the extra CPU overhead
involved in compressing and uncompressing track data.

BE AWARE HOWEVER, that as is currently the case with compressed dasd,
neither your base compressed dasd file nor any individual shadow file can
grow beyond 2GB in size. This is a limitation of the current implementation
of the compressed dasd format and there is unfortunately no way around it.
Greg Smith (the Hercules developer who wrote our current implementation) has
mentioned his plans to try and address this limitation, but alas he seems to
no longer be active in Hercules development and none of the remaining still
active Hercules developers has taken up the challenge of doing it.

HTH

["Fish" (David B. Trout)]

[...]

Post by "Fish" (David B. Trout)
Shadow files are only support on compressed dasd
(CCKD and/or CFBA). They are not support on regular
uncompressed CKD format dasd. [...]

c/support/supported/