On 10/07/97 13:31:50 you wrote:
Maybe it's the wrong question, but I remember from other drive types that once you drop into start-stop mode (or shuffling), the throughput goes through the floor. Our SE thought that a 7000 being fed below streaming speed might be actually slower than a 4000 being fed at the same speed.
Hmmm... I must admit ignorance in this area; I suppose it is possible, but it's not something I would believe off the cuff.
I agree that network backup is not great, but we're managing (just about) to get it to work at the moment using amanda and exabytes. I'd like to keep to one system, so we'll probably modify amanda to use the DLT (either locally or on the filer).
Has anyone any hard figures for backup speeds both locally on a filer and remotely via 100Mbps ethernet and rmt or rsh? We don't have anything that supports NDMP at the moment, but might consider Budtool, though it doesn't support all the machines we have at the moment.
Well, I have some numbers for FDDI.... rmt was abyssmal (500 K/sec), but that was several releases ago. A more recent release, uses a third host to rsh a piped dump and restore across a dedicated FDDI network, drove the tape drive much closer to it's limit, but I don't have exact numbers. 100Mbps ethernet isn't great but I would expect you'd see numbers much closer to local backup speed if you use rsh, but still not as fast as local.
Our main interest in the 7000 is capacity (single tape backup at the moment), rather than speed.
What if it takes 2 tapes? Are you going to get a 7000 stacker, or will you have to spend a lot of effort breaking the backup into pieces? At least a 4000 stacker will be able to keep up with your expansion.
FYI, my experience with 7000 on the filer suggests that the capacity isn't as great as you might hope. A DLT-IV cartridge on a 4000 could often get 35-40GB on it (almost max 2:1 compression), but on a 7000 I could only get about 50GB, not the 60-70GB expected with max compression. It was not clear if this was a Netapp issue or a 7000 issue... perhaps they have resolved it? You would have to inquire and find out.
I'm told that they've now released a wide card supported on the F230 in the latest release, so you can attach a 7000.
Neato. I wish they'd update the web pages to actually reflect this.
Bruce