Video Screencast Help

hardware compression disabled

Created: 19 Nov 2009 • Updated: 18 Jun 2010 | 9 comments
duschi's picture

Hi commununity,

sorry about my poor English ;-)

here is one more discussion about compression and Backup Exec:

symptom: tape hardware compression is disabled during start of Backup Exec services

proof:
- stopping all services of Backup Exec
- start LTT and generate a support ticket, shows hardware compression disabled!
- using LTT configuration utility setting compression to enable
- verify setting by using the support ticket function again - compression is enabled
- verify setting by using LTT test utility compression test, reporting 2.16 to 2.31 :-)
- starting Backup Exec services and after that immediately stopping them
- verify setting by using the support ticket function of LTT again - compression is DISABLED!

-> this proves that no job configuration causes this issue - whats going on here?

what we did:
- changed tape drive - HP did!
- downgrading firmware in tape WP8A to WP86
- using new media
- verifying drivers, service packs, etc.

configuration:
- Microsoft SBS 2003 R2
- Backup Exec 12.0 Rev. 1364 SP3
- HP DAT 160 firmware WP8A / downgraded to WP86, driver Symantec v5.1
- Adaptec 29160LP with latest adaptec driver v6.4.630.100

I am sorry, but I cannot say if compression was ever working correctly, because the critical
amount of data was reached in september (about 83.000.000.000 bytes)

Thank you for helping me out ...

Thomas

 

Comments 9 CommentsJump to latest comment

Ben L.'s picture

Thomas,

When Backup Exec first communicates with the tape devices it turns off compression, this is by design.  When you run a backup job with hardware compression enabled in the job settings, Backup Exec will turn compression back on at the drive right before it starts writing data.

See this document to verify compression is getting enabled.
http://seer.entsupport.symantec.com/docs/287662.htm

If this response answers your concern, please mark it as a "solution"

Ken Putnam's picture

From the devices tab, if you right click the drive \properties  is the option "enable hardware compression" checked?

If this response answers your concern, please mark it as a "solution"

duschi's picture

Hi,

@ Ben: thanks, this explains the behaviour ...  /I will study this document and will give you a report

@ Ken: checked once, twice ... compression is ALWAYS reported as ENABLED! I tried different compression options in my job configuration (hardware, else none - hardware, else software), but
the result is everytime the same, backup reaches about 80GB and stops...

Thanks, any more ideas?

duschi's picture

Hi Ben,

I did the trace as decribed in document ID 287662. I extracted the beginning of the backup, about 220 events, into a textfile (about 190kb). The "mode select6" operations look like as expected and the "mode sense6" do as well. After the last "mode select6" command the "mode sense6" output changes completely

All "mode sense6" command data looks like this:
Data
00 00 10 00 0F 0E C0 80 00 00 00 20 00 00 00 00 ........... ....
00 00 00 00
The "mode sense6" command data looks like this (this is what we expected - rihght?):
13 00 10 00 0F 0E C0 80 00 00 00 20 00 00 00 00 ........... ....
00 00 00 00

An this is the last pair:

(mode select6) Data
00 00 10 00 0F 0E C0 80 00 00 00 20 00 00 00 00 ........... ....
00 00 00 00
followed by (mode sense6) Data
0B 00 10 08 48 00 00 00 00 01 00 00

followed by

READ_POSITION
MODE_SENSE6
WRITE6
WRITE_FILEMARKS
READ_POSITION
MODE_SENSE6
READ_POSITION
WRITE6 (continues ...)

... any more ideas - thanks a lot,

Thomas

Ben L.'s picture

Thomas,

Can you attach the .bin file from tracer to your post so I can review the entire log?

If this response answers your concern, please mark it as a "solution"

duschi's picture

.bin file created but don't know how to attach ...

Ben,
sorry for my late response, but I had a tricky job and some trouble the last days ...

can you assist me in "attaching a file" to this discussion?

Thanks a lot,

Thomas

duschi's picture

Ben,
sorry for my late response, but I had a tricky job and some trouble the last days ...

can you assist me in "attaching a file" to this discussion?

Thanks a lot,

Thomas

Ben L.'s picture

Thomas,

I reviewed the .bin file this morning.  Compression is enabled on the drive during the backup.  The event below is from the tracer log showing that compression is enabled right before the job starts writing data.

Event:      1073  Start: 10:08:03.311  Stop:  10:08:03.311  Duration:  0.000000
SCSI Address: 02:00:03:00
Function                                SRB_FUNCTION_EXECUTE_SCSI
SCSI Status                             SCSISTAT_GOOD
Sense Length                            0
Data Length                             20
Driver Result                           STATUS_SUCCESS

Raw CDB
15 10 00 00 14 00                               ......

CDB Operation                           MODE_SELECT6
 LUN                                    0
 PF                                     True
 SP                                     False
 Parameter List Length                  20
 Control                                0x00
Data
00 00 10 00 0F 0E C0 80 00 00 00 20 00 00 00 00 ........... ....
00 00 00 00 

I would suggest getting in touch with your hardware vendor at this point.  They are going to be your best bet for resolving the issue

If this response answers your concern, please mark it as a "solution"