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Whats your DDS4 Speed?

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Aaron McKee
Occasional Visitor

Whats your DDS4 Speed?

Although PAT told me I have a transfer rate of 2.68 MB/sec, my HP DDS4 drive completed its backup at an average of 3.98 MB/sec! How about yours? :D
7 REPLIES
Leif Halvarsson_2
Honored Contributor

Re: Whats your DDS4 Speed?

Hi,

Have you got the correct spec. for your drive. Look at:
http://h18006.www1.hp.com/products/quickspecs/11784_div/11784_div.html

Specifications for DDS 4 drives should be:

3 MB/sec native data transfer speed, 6 MB/sec with 2:1 compression
Aaron McKee
Occasional Visitor

Re: Whats your DDS4 Speed?

Backup completed on 2/13/2004 at 7:59:43 AM.
Backed up 130811 files in 10937 directories.
Processed 129,512,135,932 bytes in 8 hours, 37 minutes, and 19 seconds.
Throughput rate:
238.8 MB/min

So that would be at 2:1 compression, which means I'm about 2MB/sec slower than the specs show. Which is a bit strange since these 10K seagate drives are extremely fast. Well that kind of sucks! :)
Aaron McKee
Occasional Visitor

Re: Whats your DDS4 Speed?

Analyzed the drive just for the hell of it:

Total fragmentation=37 %
File fragmentation=71 %
Free space fragmentation=4 %


Would it make a difference if I defragged?
Leif Halvarsson_2
Honored Contributor
Solution

Re: Whats your DDS4 Speed?

Hi,
You back up about 130 000 files, total 130GB of data. The average filesize is 1MB. That filesize should not slow down backup (as it does with small files).

All that data can't fit on one media, how many medias is used for a complete backup. If you know the number of medias used then you can calculate the compression ratio for your data (2-1 ratio don't apply to all data). If the ratio is less then 2-1 the throughput also will decrease.
Aaron McKee
Occasional Visitor

Re: Whats your DDS4 Speed?

Its a 6 tape auto loader, looks like it used all 5 tapes (#6 is cleaner)
Aaron McKee
Occasional Visitor

Re: Whats your DDS4 Speed?

LOG:
======================================================================
Job server: GPCMAIL
Job name: Full Weekly
Job started: Thursday, February 12, 2004 at 11:00:07 PM
Job type: Backup
Log file: BEX00.txt
======================================================================

Drive and media information from media mount:
Changer Name: HP 1
Drive Name: HP 1
Media Slot: 5
Media Cartridge Label: GPC 5
Targeted Media Set Name: GPC Media Set

======================================================================
Job Operation - Backup
Media operation - append.
Hardware compression enabled.
======================================================================

Media Name: "Media created 2/12/2004 11:00:08 PM"
Backup of "I: GPC Clients"
Backup set #1 on storage media #1
Backup set description: "Full Weekly"
Backup Type: NORMAL - Back Up Files - Reset Archive Bit
Backup started on 2/12/2004 at 11:06:06 PM.

Drive and media information from media mount:
Changer Name: HP 1
Drive Name: HP 1
Media Slot: 2
Media Cartridge Label: GPC 2
Targeted Media Set Name: GPC Media Set
Backup set #1 on storage media #2

Drive and media information from media mount:
Changer Name: HP 1
Drive Name: HP 1
Media Slot: 3
Media Cartridge Label: GPC 3
Targeted Media Set Name: GPC Media Set
Backup set #1 on storage media #3

Drive and media information from media mount:
Changer Name: HP 1
Drive Name: HP 1
Media Slot: 4
Media Cartridge Label: GPC 4
Targeted Media Set Name: GPC Media Set
Backup set #1 on storage media #4

Drive and media information from media mount:
Changer Name: HP 1
Drive Name: HP 1
Media Slot: 1
Media Cartridge Label: GPC 1
Targeted Media Set Name: GPC Media Set
Backup set #1 on storage media #5

Backup completed on 2/13/2004 at 7:59:43 AM.
Backed up 130811 files in 10937 directories.
Processed 129,512,135,932 bytes in 8 hours, 37 minutes, and 19 seconds.
Throughput rate: 238.8 MB/min
Marino Meloni_1
Honored Contributor

Re: Whats your DDS4 Speed?

try to use system performance in L&TT, there you can change the blok size and compression so that you can tune your backup.