Jump to content
Canonball

Backup spped with LTO-4 SAS drive

Recommended Posts

Hello,

 

I installed Retrospect 7.6 on a Windows 2003R2 single server with a SAS RAID6.

Backup to a LTO-4 SAS connection drive shows a backup speed of 35 MByte/s. Compared with ARCserve installed before it is half of the speed (65-70 MByte/s).

 

Do you have any ideas?

 

Thanks,

Canonball

Share this post


Link to post
Share on other sites

Yes, it is:

 

IBM 3580 Ultrium 4 Tape Drive

Manufacturer: IBM

Interface: SAS

Media: LTO

 

Windows

Support Status Qualified

Minimum Version Required 7.5

Minimum Driver Update 7.5.11.100

Advanced Driver Kit (Retro 4.x only) N/A

Minimum Firmware Version

 

Share this post


Link to post
Share on other sites

I know this works for SCSI. You can try it:

 

Also, here's registry keys that users can try to adjust to make their SCSI or FC cards go faster:

-----------------------------------------------------------------
HKEY_LOCAL_MACHINE
  HARDWARE
     DEVICEMAP
        SCSI
           SCSIPORT   (Driver --> i.e. Symmpi)
  SYSTEM
     CURRENTCONTROLSET
        SERVICES
           (Driver)
              PARAMETERS
                 DEVICE -> MaximumSGList

The MaximumSGList value is the one you want to set:

(formula: if value 65, 65 - 1 = 64 x 4K = 256K Transfers)

65 = 256K transfers
33 = 128K transfers
17 = 64k transfers 

Share this post


Link to post
Share on other sites

Are you using Retrospect's built-in speed indicators? If so, I have seen this show completely incorrect results. For example, when transferring data from hard drive to tape, I've seen Retrospect tell me that it's copying data at 8mb/minute, but it finished several gigabytes of data in just a few minutes. I've also seen it say that it's copying data over at 113,000 mb/minute, but the time to copy the data didn't match up with this superhuman speed.

 

Is is possible that your data is getting transferred at the correct speed with Retrospect simply underreporting the speed?

Edited by Guest

Share this post


Link to post
Share on other sites

I had another thought on this. Are you using Retrospect's built-in software compression, or the drive's native compression? If you're using the former, than performance is going to be much slower than if using the later.

Share this post


Link to post
Share on other sites

If you're using the drive's native compression, you don't need to use the software compression. The only reason to use software compression (in my experience, anyway) is if:

 

1. You are encrypting the data going to the tapes.

 

or

 

2. You are backing up to a device that does not support hardware compression (e.g., a hard drive).

Share this post


Link to post
Share on other sites

Robin...

 

Do you have any ideas on why this is slower than Arcserv? I haven't ever tried the CA product. If retro is slower, is there anything in the development that increases speed?

Share this post


Link to post
Share on other sites

I have seen LTO with Retrospect get 2 or 3 GB per minute. Every environment is going to be different.

Edited by Guest

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×