NDMP - How should it be connected?


We have a FAS2040 with dual controllers so an active/active configuration. Our disk shelf connects via SAS so this leave our FCP ports free.

We wanted to use NDMP for backups straight to our LTO5 fibre tape drive. I connected our tape drive via fibre straight to our 8Gb fibre switch. The tape drive is only capable of 4Gb but thats ok. When connecting our FAS2040 to the fibre switch I saw that each controller has 2 fibre sockets. This means our fas2040 has 4 in total. I connected a fibre cable into one socket on each controller to the fibre switch. The backups run fine using backup exec and the NDMP option but they dont run as quickly as I was expecting. I tried looking at the fibre switch and it shows the tape drive running at 4Gb but the 2 NetApp connections were only running at 2Gb each. If I tried forcing the sockets on the switch to 4Gb the netapp devices would just go offline. I tried looking in the netapp documentation but couldnt find any obvious way to set the speeds on the FCP ports. For an initiator at least.

This started me wondering about the cable connections. Since each controller board has 2 fibre sockets each are you meant to connect both to the fibre switch so it combines up to 4Gb? It sounds a bit odd to me but im a bit stumpted as to why the speed is so dissapointing.

I've read allot about the types of data your backing up having an impact. Our fas2040s only hold VM's so in theory it's just a few number of big fies. We are also running NDMP at version 4 which is another common suggestion.

Many thanks for any suggestions.


Re: NDMP - How should it be connected?

FAS2040 has 4GBit Ports and back in the days was shipped with 4GBit SFPs as well. You can force port speed like this

fcp config 0a mediatype ptp speed 4

fcp config 0b mediatype ptp speed 4

Re: NDMP - How should it be connected?

Hi thomas.glodde,

Many thanks for the advice but unfortunatley those commands didnt work. It tells me there are no target adaptors in the system. I guess thats because the Netapp box is the initator and the tape drive is the target. I also tried taking the switch socket offline before doing the suggested commands but nothing would let me configure the port speed.

Re: NDMP - How should it be connected?

does "storage show adapter" show 2GB or 4GB?  I wonder if 2GB SFPs are installed... although it usually is a bottleneck elsewhere.  You can manually run "dump 0f null volname" to do a null dump and see the fastest you can write without a target device...delete the snapshot for backup after the null dump completes.  If it is much faster than the tape backup you can troubleshoot the connection more, but this will show the best case read you can get to any device since it removes the tape and fc connection.