Re: Splitting files across tapes

2005-06-09 Thread Prather, Wanda
Wow, that's interesting!

I'll set up some tests myself.  Thanks!

-Original Message-
From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of
William Colwell
Sent: Wednesday, June 08, 2005 5:59 PM
To: ADSM-L@VM.MARIST.EDU
Subject: Re: Splitting files across tapes


Hi Wanda,

I have some real data which might mean something for your question.  I
am in
the process of moving all the files on one server into collocation
groups.
I am copying tapes to sequential disk to do this.  The sizes of full
disk
volumes vary a lot which might mean that an aggregate won't go across
disk
base sequential volumes.  The data, see the Est. cap for the full
volumes --

tsm: XXXq vol stg=seqdisk2

Volume Name  Storage Device Estimated
Pct  Volume
 Pool Name   Class Name  Capacity
Util  Status
 --- -- -
- 
/seqdisk2/cgseq2_000 SEQDISK2SEQDISK2 2,016.0
100.0   Full
/seqdisk2/cgseq2_001 SEQDISK2SEQDISK2 2,037.0
100.0   Full
/seqdisk2/cgseq2_002 SEQDISK2SEQDISK2 2,016.9
100.0   Full
/seqdisk2/cgseq2_003 SEQDISK2SEQDISK2 2,036.7
100.0   Full
/seqdisk2/cgseq2_004 SEQDISK2SEQDISK2 2,043.4
100.0   Full
/seqdisk2/cgseq2_005 SEQDISK2SEQDISK2 2,045.1
100.0   Full
/seqdisk2/cgseq2_006 SEQDISK2SEQDISK2 2,035.0
100.0   Full
/seqdisk2/cgseq2_007 SEQDISK2SEQDISK2 2,042.4
100.0   Full
/seqdisk2/cgseq2_008 SEQDISK2SEQDISK2 2,008.0
100.0   Full
/seqdisk2/cgseq2_009 SEQDISK2SEQDISK2 2,041.1
100.0   Full
/seqdisk2/cgseq2_00A SEQDISK2SEQDISK2 2,034.3
100.0   Full
/seqdisk2/cgseq2_00B SEQDISK2SEQDISK2 2,048.0
6.8 Filling
/seqdisk2/cgseq2_00C SEQDISK2SEQDISK2 2,048.0
0.0  Empty
/seqdisk2/cgseq2_00D SEQDISK2SEQDISK2 2,048.0
0.0  Empty
/seqdisk2/cgseq2_01F SEQDISK2SEQDISK2 2,048.0
0.0  Empty
/seqdisk2/cgseq2_020 SEQDISK2SEQDISK2 2,024.7
100.0   Full

Hope this helps,

Bill Colwell


 -Original Message-
 From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED]
 On Behalf Of Prather, Wanda
 Sent: Tuesday, June 07, 2005 10:07 AM
 To: ADSM-L@VM.MARIST.EDU
 Subject: Re: Splitting files across tapes

 Hi Richard,

 Thanks for responding; maybe this will give you something to
 amuse your
 brain over morning coffee.

 The reason for the question, mgmt here is considering going
 to all-disk
 backup (for onsite).
 So our sequential volumes will be disk instead of tape.

 We occasionally have issues with mis-classified data ending up on a
 tape, and the tape has to be pulled and destroyed.
 No big deal with a tape.  Big deal when the volume is a 1 TB raid
 array!

 So the question comes, what is the likelihood that we would
 contaminate
 TWO 1 TB raid arrays with a split file?

 I think for sequential volumes, TSM doesn't know that the volume is
 full, until it tries to write to it.
 If there isn't space for the next block, then it mounts a
 scratch and
 rewrites the block to a new tape, yes?

 So can I assume that the file would have to be larger than an
 aggregate
 (what is that, MOVESIZETHRESH?) in order to end up split
 across 2 tapes?

 Thanks for lending brain power!

 W





 -Original Message-
 From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED]
 On Behalf Of
 Richard Sims
 Sent: Tuesday, June 07, 2005 9:55 AM
 To: ADSM-L@VM.MARIST.EDU
 Subject: Re: Splitting files across tapes


 Hi, Wanda -

 I don't believe there is any rule, per se: it is just the case that
 the drive finally reaches end-of-volume (EOV - TSM msg ANR8341I).
 This results in the subsequent data being written in a spanned
 Segment on a new volume.

 Richard Sims

 On Jun 7, 2005, at 9:36 AM, Prather, Wanda wrote:

  Does anyone happen to know what rules TSM uses to decide when to
  split a
  backup file/aggregate across 2 tapes?
  Or can you point me to a document?
 
  (Management wants to know.)
 


Re: Splitting files across tapes

2005-06-08 Thread William Colwell
Hi Wanda,

I have some real data which might mean something for your question.  I am in
the process of moving all the files on one server into collocation groups.
I am copying tapes to sequential disk to do this.  The sizes of full disk
volumes vary a lot which might mean that an aggregate won't go across disk
base sequential volumes.  The data, see the Est. cap for the full volumes --

tsm: XXXq vol stg=seqdisk2

Volume Name  Storage Device Estimated
Pct  Volume
 Pool Name   Class Name  Capacity
Util  Status
 --- -- -
- 
/seqdisk2/cgseq2_000 SEQDISK2SEQDISK2 2,016.0
100.0   Full
/seqdisk2/cgseq2_001 SEQDISK2SEQDISK2 2,037.0
100.0   Full
/seqdisk2/cgseq2_002 SEQDISK2SEQDISK2 2,016.9
100.0   Full
/seqdisk2/cgseq2_003 SEQDISK2SEQDISK2 2,036.7
100.0   Full
/seqdisk2/cgseq2_004 SEQDISK2SEQDISK2 2,043.4
100.0   Full
/seqdisk2/cgseq2_005 SEQDISK2SEQDISK2 2,045.1
100.0   Full
/seqdisk2/cgseq2_006 SEQDISK2SEQDISK2 2,035.0
100.0   Full
/seqdisk2/cgseq2_007 SEQDISK2SEQDISK2 2,042.4
100.0   Full
/seqdisk2/cgseq2_008 SEQDISK2SEQDISK2 2,008.0
100.0   Full
/seqdisk2/cgseq2_009 SEQDISK2SEQDISK2 2,041.1
100.0   Full
/seqdisk2/cgseq2_00A SEQDISK2SEQDISK2 2,034.3
100.0   Full
/seqdisk2/cgseq2_00B SEQDISK2SEQDISK2 2,048.0
6.8 Filling
/seqdisk2/cgseq2_00C SEQDISK2SEQDISK2 2,048.0
0.0  Empty
/seqdisk2/cgseq2_00D SEQDISK2SEQDISK2 2,048.0
0.0  Empty
/seqdisk2/cgseq2_01F SEQDISK2SEQDISK2 2,048.0
0.0  Empty
/seqdisk2/cgseq2_020 SEQDISK2SEQDISK2 2,024.7
100.0   Full

Hope this helps,

Bill Colwell


 -Original Message-
 From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED]
 On Behalf Of Prather, Wanda
 Sent: Tuesday, June 07, 2005 10:07 AM
 To: ADSM-L@VM.MARIST.EDU
 Subject: Re: Splitting files across tapes

 Hi Richard,

 Thanks for responding; maybe this will give you something to
 amuse your
 brain over morning coffee.

 The reason for the question, mgmt here is considering going
 to all-disk
 backup (for onsite).
 So our sequential volumes will be disk instead of tape.

 We occasionally have issues with mis-classified data ending up on a
 tape, and the tape has to be pulled and destroyed.
 No big deal with a tape.  Big deal when the volume is a 1 TB raid
 array!

 So the question comes, what is the likelihood that we would
 contaminate
 TWO 1 TB raid arrays with a split file?

 I think for sequential volumes, TSM doesn't know that the volume is
 full, until it tries to write to it.
 If there isn't space for the next block, then it mounts a
 scratch and
 rewrites the block to a new tape, yes?

 So can I assume that the file would have to be larger than an
 aggregate
 (what is that, MOVESIZETHRESH?) in order to end up split
 across 2 tapes?

 Thanks for lending brain power!

 W





 -Original Message-
 From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED]
 On Behalf Of
 Richard Sims
 Sent: Tuesday, June 07, 2005 9:55 AM
 To: ADSM-L@VM.MARIST.EDU
 Subject: Re: Splitting files across tapes


 Hi, Wanda -

 I don't believe there is any rule, per se: it is just the case that
 the drive finally reaches end-of-volume (EOV - TSM msg ANR8341I).
 This results in the subsequent data being written in a spanned
 Segment on a new volume.

 Richard Sims

 On Jun 7, 2005, at 9:36 AM, Prather, Wanda wrote:

  Does anyone happen to know what rules TSM uses to decide when to
  split a
  backup file/aggregate across 2 tapes?
  Or can you point me to a document?
 
  (Management wants to know.)
 


Splitting files across tapes

2005-06-07 Thread Prather, Wanda
Does anyone happen to know what rules TSM uses to decide when to split a
backup file/aggregate across 2 tapes?
Or can you point me to a document?

(Management wants to know.)


Re: Splitting files across tapes

2005-06-07 Thread Richard Sims

Hi, Wanda -

I don't believe there is any rule, per se: it is just the case that
the drive finally reaches end-of-volume (EOV - TSM msg ANR8341I).
This results in the subsequent data being written in a spanned
Segment on a new volume.

   Richard Sims

On Jun 7, 2005, at 9:36 AM, Prather, Wanda wrote:


Does anyone happen to know what rules TSM uses to decide when to
split a
backup file/aggregate across 2 tapes?
Or can you point me to a document?

(Management wants to know.)



Re: Splitting files across tapes

2005-06-07 Thread Prather, Wanda
Hi Richard,

Thanks for responding; maybe this will give you something to amuse your
brain over morning coffee.

The reason for the question, mgmt here is considering going to all-disk
backup (for onsite).
So our sequential volumes will be disk instead of tape.

We occasionally have issues with mis-classified data ending up on a
tape, and the tape has to be pulled and destroyed.
No big deal with a tape.  Big deal when the volume is a 1 TB raid
array!

So the question comes, what is the likelihood that we would contaminate
TWO 1 TB raid arrays with a split file?

I think for sequential volumes, TSM doesn't know that the volume is
full, until it tries to write to it.
If there isn't space for the next block, then it mounts a scratch and
rewrites the block to a new tape, yes?

So can I assume that the file would have to be larger than an aggregate
(what is that, MOVESIZETHRESH?) in order to end up split across 2 tapes?

Thanks for lending brain power!

W





-Original Message-
From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of
Richard Sims
Sent: Tuesday, June 07, 2005 9:55 AM
To: ADSM-L@VM.MARIST.EDU
Subject: Re: Splitting files across tapes


Hi, Wanda -

I don't believe there is any rule, per se: it is just the case that
the drive finally reaches end-of-volume (EOV - TSM msg ANR8341I).
This results in the subsequent data being written in a spanned
Segment on a new volume.

Richard Sims

On Jun 7, 2005, at 9:36 AM, Prather, Wanda wrote:

 Does anyone happen to know what rules TSM uses to decide when to
 split a
 backup file/aggregate across 2 tapes?
 Or can you point me to a document?

 (Management wants to know.)



Re: Splitting files across tapes

2005-06-07 Thread Richard Sims

On Jun 7, 2005, at 10:06 AM, Prather, Wanda wrote:


Hi Richard,

Thanks for responding; maybe this will give you something to amuse
your
brain over morning coffee.

The reason for the question, mgmt here is considering going to all-
disk
backup (for onsite).
So our sequential volumes will be disk instead of tape.

We occasionally have issues with mis-classified data ending up on a
tape, and the tape has to be pulled and destroyed.
No big deal with a tape.  Big deal when the volume is a 1 TB raid
array!


I would recommend against destroying such RAID arrays - sounds
expensive. :-))


So the question comes, what is the likelihood that we would
contaminate
TWO 1 TB raid arrays with a split file?

I think for sequential volumes, TSM doesn't know that the volume is
full, until it tries to write to it.
If there isn't space for the next block, then it mounts a scratch
and
rewrites the block to a new tape, yes?

So can I assume that the file would have to be larger than an
aggregate
(what is that, MOVESIZETHRESH?) in order to end up split across 2
tapes?


A magic word in your scenario is sequential. This means you will be
using
File type devclass. TSM 5.3 allows you to make the volume size
whatever you
want, up to the limits of the file system. A judicious choice will
make for
a size which affords nice capacity while not being ponderous when you
have
to deal with a stray. And I should think that you could deal with the
stray
by doing an Expire or Delete Backup command from the client, perhaps
followed by a MOVe Data ... RECONStruct=Yes on the containing server
volume
if there needs to be assured erasure of the goner. With this, may it
be the
case that concerns over volumes and spanning are unwarranted?

File type devclass volumes may incite more predictive processing in TSM,
given that there is the advantage of known size, whereas the actual
length
of a tape is not known. That is, TSM will probably know there is
insufficient
space for the next Aggregate, or clump of a file whose size is larger
than
an Aggregate, so as to go to a new volume. (Now, I don't know for
certain,
but have to suspect that the File volume's size is uniquely tracked
in the
db rather than simply taken from the devclass spec, given that the
devclass
MAXCAPacity can be updated at will. Thus, the size of volumes over time
should be deterministic.)

If there's definitive doc about all this, I have not yet encountered it.
Someone out there may have more info.



Thanks for lending brain power!


If I were really smart I'd be charging for exposition of what I know,
rather than working for a living.  :-)

Richard Sims


Re: Splitting files across tapes

2005-06-07 Thread Johnson, Milton
Are you talking about a 1TB VOLUME, or several smaller volumes (say
10GB) on a 1TB array? 

H. Milton Johnson
 
-Original Message-
From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of
Prather, Wanda
Sent: Tuesday, June 07, 2005 9:07 AM
To: ADSM-L@VM.MARIST.EDU
Subject: Re: Splitting files across tapes

Hi Richard,

Thanks for responding; maybe this will give you something to amuse your
brain over morning coffee.

The reason for the question, mgmt here is considering going to all-disk
backup (for onsite).
So our sequential volumes will be disk instead of tape.

We occasionally have issues with mis-classified data ending up on a
tape, and the tape has to be pulled and destroyed.
No big deal with a tape.  Big deal when the volume is a 1 TB raid
array!

So the question comes, what is the likelihood that we would contaminate
TWO 1 TB raid arrays with a split file?

I think for sequential volumes, TSM doesn't know that the volume is
full, until it tries to write to it.
If there isn't space for the next block, then it mounts a scratch and
rewrites the block to a new tape, yes?

So can I assume that the file would have to be larger than an aggregate
(what is that, MOVESIZETHRESH?) in order to end up split across 2 tapes?

Thanks for lending brain power!

W





-Original Message-
From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of
Richard Sims
Sent: Tuesday, June 07, 2005 9:55 AM
To: ADSM-L@VM.MARIST.EDU
Subject: Re: Splitting files across tapes


Hi, Wanda -

I don't believe there is any rule, per se: it is just the case that the
drive finally reaches end-of-volume (EOV - TSM msg ANR8341I).
This results in the subsequent data being written in a spanned Segment
on a new volume.

Richard Sims

On Jun 7, 2005, at 9:36 AM, Prather, Wanda wrote:

 Does anyone happen to know what rules TSM uses to decide when to split

 a backup file/aggregate across 2 tapes?
 Or can you point me to a document?

 (Management wants to know.)