ADSM-L

[ADSM-L] NetApp VTL (Virtual Tape Library 600) - after some hours of testing

2008-02-22 10:19:38
Subject: [ADSM-L] NetApp VTL (Virtual Tape Library 600) - after some hours of testing
From: Stefan Folkerts <stefan.folkerts AT ITAA DOT NL>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Fri, 22 Feb 2008 16:19:01 +0100
Hi,

I currently have at my disposal a NetApp VTL 600 for testing purposes.

Setup :

It's a single shelf VTL containing 14 500GB SATA disks including 1
hotspare.

I have a Windows server attached via FC, TSM 5.4 installed on the
server.
The VTL is configured to be a NetApp library and it's simulating to have
4 IBM LTO3 drives.

Installation :

The default TSM device drivers that come with TSM contain the driver for
this 'netapp' library and of course the LTO3 drives pose no problem
since I can use the default IBM drivers for those as well.


My findings so far :

I inserted 50 virtual tapes in the VTL and started a label libv command
with a checkin=scratch.
This took a whole 30 somewhat secondes to complete..50 "tapes" labeled
and checked in.
It looks like TSM just can't interface with a library (be it virtual of
not) faster than this.

An audit libr without a checklabel=barcode seems to mount the first
virtual tape and then just sit there doing nothing.

DB backup (ok, it's a small db, but still)

>From the actual start of the backup to the point where the volume is
opened takes 1 second.
The whole thing for giving the command to the completion and dismount is
done in 33 secondes.

15-2-2008 13:21:16 ANR2017I Administrator ADMIN issued command: BACKUP
DB type=full devclass=LTOCLASS1 
15-2-2008 13:21:24 ANR0984I Process 236 for DATABASE BACKUP started in
the BACKGROUND at 13:21:25.
15-2-2008 13:21:24 ANR2280I Full database backup started as process 236.
15-2-2008 13:21:24 ANR0405I Session 845 ended for administrator ADMIN
(WinNT).
15-2-2008 13:21:25 ANR8337I LTO volume 00001L7 mounted in drive
MT1.1.0.2 (mt1.1.0.2).
15-2-2008 13:21:25 ANR0513I Process 236 opened output volume 00001L7.
15-2-2008 13:21:25 ANR1360I Output volume 00001L7 opened (sequence
number 1).
15-2-2008 13:21:33 ANR4554I Backed up 7040 of 14162 database pages.
15-2-2008 13:21:44 ANR4554I Backed up 14080 of 14162 database pages.
15-2-2008 13:21:48 ANR1361I Output volume 00001L7 closed.
15-2-2008 13:21:48 ANR0515I Process 236 closed volume 00001L7.
15-2-2008 13:21:49 ANR4550I Full database backup (process 236) complete,
14162 pages copied.
15-2-2008 13:21:49 ANR0985I Process 236 for DATABASE BACKUP running in
the BACKGROUND completed with completion state SUCCESS at 13:21:50.
15-2-2008 13:21:49 ANR8336I Verifying label of LTO volume 00001L7 in
drive MT1.1.0.2 (mt1.1.0.2).
15-2-2008 13:21:49 ANR8468I LTO volume 00001L7 dismounted from drive
MT1.1.0.2 (mt1.1.0.2) in library LB1.0.0.2.

13:25:18   localhost : q stgpool

Storage      Device       Estimated    Pct    Pct  High  Low  Next
Stora-
Pool Name    Class Name    Capacity   Util   Migr   Mig  Mig  ge Pool

                                                    Pct  Pct  
-----------  ----------  ----------  -----  -----  ----  ---
-----------
ARCHIVEPOOL  DISK             0.0 M    0.0    0.0    90   70  DISKPOOL

BACKUPPOOL   DISK             0.0 M    0.0    0.0    90   70  DISKPOOL

DISKPOOL     DISK              20 G   31.3   31.3   100   99  LTOPOOL1

LTOPOOL1     LTOCLASS1    105,808 G    0.1    0.8    90   70

SPACEMGPOOL  DISK             0.0 M    0.0    0.0    90   70



13:32:11   localhost : show transferstats diskpool
Statistics for last migration from pool DISKPOOL
   Start date/time: 02/15/2008 13:27:36
   Elapsed time: 165 seconds
   Total wait time: 1 seconds
   Number of participating processes: 4
   Total duration of all processes: 165 seconds
   Total physical files: 166
   Total logical files: 22003
   Total bytes: 6572945408
   Average logical files per physical file: 132.5
   Average physical file size: 38668.0 KB
   Number of batch/file transactions ended: 15
   Number of batch transactions aborted: 0
   Number of file transactions started: 0
   Number of file transactions aborted: 0

No storage pool backup information available for DISKPOOL.

Guess we got 38MB/s on that migration from a slow internal disk diskpool
-> VTL.

A funny this is that you can set the size of the virtual volumes in the
VTL independent of the drive type you select and configure in TSM.

I selected a 10GB data limit per volume on these LTO3 virtual volumes
and this is what I get :

13:37:00   localhost : q vol

Volume Name               Storage      Device      Estimated    Pct
Volume 
                          Pool Name    Class Name   Capacity   Util
Status 
------------------------  -----------  ----------  ---------  -----
--------
00001L3                   LTOPOOL1     LTOCLASS1     9,510.2  100.0
Full  
00001L4                   LTOPOOL1     LTOCLASS1    16,113.0  100.0
Full  
00001L5                   LTOPOOL1     LTOCLASS1    20,840.4  100.0
Full  
00001L6                   LTOPOOL1     LTOCLASS1    19,088.1  100.0
Full  
00001L8                   LTOPOOL1     LTOCLASS1   800,000.0    0.6
Filling 
E:\TSMDATA\SERVER1\DISK-  DISKPOOL     DISK         20,000.0    0.0
On-Line 
 1.DSM


There we see the VTL compression in action as well putting out something
that comes close to 1:2 compression on most volumes.

The range I wanted to use was 00001L3 -> 0999L3 but the VTL turned that
into 00001L3 -> 00001L8 :)

I can't really test performance because of the limitations in the
configuration I am given.

But even under small loads you can see on of the nice features of this
VTL come to life, the system automatically spreads it's load over the
disks so that when I run 4 streams to tape all disks receive about the
same amount of load, and this is balanced with every stream of data
coming into the VTL.
I can't say anything but that is works as expected.

If any of you would like to see something tested on a VTL like
this..maybe I can be of service :) !

 Regards,

   Stefan

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