Optimising Backup Exec 12.5 Performance

[NeilMurphy65]

Hi,

I have been working on some issues with Backup Exec for a client. He has BE12.5 installed on four media servers with the SAN Shared Storage Option and CASO. Attached to the fabric is a HP MSL8096 tape library with 4 LTO-4 Ultrium 1840 fiber channel drives.

When I started looking at this, he was getting very slow backup rates, usually about 220MB/min. After searching the forums I came across some advice about tape drive settings so I made the following changes:

Block size: 64k (no change)

Buffer size: 64k -> 1MB

Buffer count: 10 -> 30

High water count: 0 -> 15

I also enabled the following:

Read SCSI Passthrough Mode
Write  SCSI Passthrough Mode
Read Single Block Mode
Write Single Block Mode

Now I'm getting 2.5GB/min which is a great improvement. However, this is still far off what the drive is capable of which is about 12GB/min.

Does anyone know how I might get closer to the theoretical maximum throughput?

Thanks,

Neil.

[Ken_Putnam]

About all your can do in addition to what you have already done is to dis-able both Single Block settings   it may or may not have much of an effect, but theoretically bypasses all buffering

[teiva-boy]

 You will NEVER NEVER EVER get near close to maximum.  LTO3/4/5 is faster than your servers are capable of spitting out data.

The best you can do is backup to local disk to the BE server, and do a duplicate of the BKF files to tape.  It's easier to backup a large contiguous file than millions of smaller ones.

2.5GB/min is not too shabby at all IMO.

[Martin_Forster1]

Hi,

i was able to reach around 5,5 GB on doing a local Backup of large files.
But i have optimized the volume for sequential usage.
I have implemented similar settings on the Backup Device like you have.
(Note, B2D2T Performance is still at this 2,x GB/min rate)

Regards

Martin Forster

[CraigV]

Hi Neil,

Sounds like you are getting probably the best speed out of your tape drive as you are backing up across the LAN.
How is your SAN SSO configured? 
SAN SSO allows you to share your SAN-attached library with all your SAN-attached servers. THe downside to this is that you need to have full installations of BEWS on all your servers, and patched to the same level to be safe.
If you don't have full versions of BEWS 12.5 in that network, you are basically just backing up your media servers across your LAN.

Laters!