Backup speeds using LTO drives ! ! ! 2

[tech187]

I am using NB 4.5 datacenter with a Dell PowerVault 136t fiber attached library in a SAN enviorment. This library is using LTO tape drives. I am only in the testing phase right now and admittedly don't know much about NB. The first few backups I ran only got about 500mb per minute backup speed. Using Arcserve 2000 on a standalone server with a smaller LTO autoloader I have got speeds over 1gb per minute. For those of you running NB with LTO drives, what kind of backup speeds are you seeing? Thanks for any info.

 

[PGPhantom]

Even at the low end of the scale i.e. assuming that you are not using any kind of compression - You should be getting around 53GB/Hour per drive.

If your PV136T is fully populated then for 6 LTO Ultrium drives you should be getting 318-636GB/Hour for the unit. i.e. You should be getting around 1GB/min per drive.

I would check the hardware configuration to start with and then the configuration of NetBackup as something is definitely not right as you are only getting DLT7000 backup speeds.

 

[tech187]

The PV-136T library I am using only has 2 drives in it and I am only using 1 of them for my testing. I agree, there is something definetly wrong. The machine I am using as my media server is a PIII with 128mb of ram. I am not sure if that would have any effect on the speed. Where does most of the work take place when a NB backup is running?

 

[PGPhantom]

There are so many things to consider when configuring backups...

On the clienst, what are your nic settings? i.e.
Duplex
Flow Control
Checksum Offloading
What are the corresponding settnigs on the switch for the same items?

For each 1MB/sec of data arriving at the server you need 5MHz CPU processing power. To calculate:
<Num of clients> * <rate in MB/sec> * 5MHz * 2 (5MHz for reading off network and 5MHz for writing to tape). E.g. 8 jobs averaging 6000KB/sec needs = 480MHz.
Memory Used = (buffer_size * num_buffers) * num_drives * MPX’ing

What are your buffer settings? i.e.
netbackup\NET_BUFFER_SZ
netbackup\db\config\SIZE_DATA_BUFFERS
netbackup\db\config\NUMBER_DATA_BUFFERS
If the files do not exist - You are using the defaults = Configured for DLT Speeds.

What is your comminucations buffer size for the clients - in the GUI - &quot;Client Propertes&quot; - &quot;Windows Client&quot; at the bottom left?

If you can get me that info - We'll take it from there. If you find the information that I give helpful, please mark it as such so that othrs may benefit from it as well.

Thanks.