NFS backup effect on network

[Paul_481]

Hi,

I want to backup an NFS filesystem using Data Protector 5.

I just want to know how will this affect the network performance in general.

The tape device is connected to the NFS client through SAN.

Thanks,

Paul

[harry d brown jr]

It depends. What does your network topology look like? Is it a switched network or a hub network? Is it 10BT/100BT/1000BT? How much data will be backed up? What kind of server are you using to back it up? What's the type of tape drive? What are your backup windows? What software are you using to backup?

live free or die
harry d brown jr

[Bill Hassell]

NFS is not a very efficient protocol for backups at all. In fact, for ANY network backup design, NEVER share the backup LAN with any other computers. Create a totally dedicated LAN connection from the NFS server to your system with the tape drive.

The second consideration is that LANs are inherently very slow compared to today's tape drives. So the tape drive may have to stop and reposition thousands of times during the backup, giving you a backup throughput of just a few megs/sec and wearing out the tape drive very rapidly. If a tape drive will backup 50Mb/sec, there is no possible way to meet this speed with a 100BaseT network. Gigabit might make it but it would require a very fast processor to keep the LAN driver overhead down.

[Paul_481]

Hello,

-HP 9000/RP8400, HPUX 11.11, 4 cpu pa8700, 8gb memory
- The two systems are connected through switch. The NFS clients is connected to the tape drive through SAN.
- 100BT
- 20Gb and 200Gb
- 8 hrs.
- Data Protector 5

The reason why we want to do this is because the local tape drive is dds. the backup time is 10-12 hours consuming 6-7 dds tapes.

By using the 6/60 LTO ultrium library, we thougt we can reduce the backup duration.

regards,

Paul

[harry d brown jr · Accepted solution]

Paul,

200GB backed up over a 100BT will take you over 8 hours, and actually probably closer to 12 (if not longer) hours (NFS is slow).

If the client is a windows box, then add another two to four hours.

Why is a 6/60 LTO attached to a client machine? Would it not be better to have that attached to your RP8400 ? If the LTO is needed on the client machine, then get an LTO 230 for the RP8400 which is less than $4000 (us dollars).


live free or die
harry d brown jr

[Paul_481]

Hi,

Actually the client is part of a SAN and the 6/60 is shared. Now the NFS server is on a different network.

I'll then just compare the performance of the backup to see which one will be faster.

Thanks everyone for the reply.

Paul

[Steven E. Protter]

The performance numbers Harry gave you are the best you will do. If both ends have a 1000 BaseT NIC and the switches support it, you will see a vast improvement in throughput.

We have one disk array and one san. Windows and HP-UX are on the same array and san. All important backups are done via the SAN. Sounds like that NFS share is the one slowdown.

After you test, this post will serve as a possible reference on how to pump up the backup speed.

SEP

[Bill Hassell]

Rather than use NFS, you'll get better performance with DataProtector over the network. NFS is a very general purpose network filesystem while DP packages the backup data to maximize throughput. However, the Ultrium tape drive (depends on which model) will seldom come up to speed and will be starved for data. This could make the 10-12 hours for DDS look pretty good. The real concern is wear on the LTO drive. If you can't keep the data streaming to the drive, it will constantly reposition and wear down the heads very quickly. You'll probably need the APA (AutoPort Aggregation) product to get the performance needed.