On Wed, July 27, 2011 17:03, Len Boyle wrote:
> David,
>
> I think the answer depends on what you mean by multi-pathing, and the
> maker of the tape drive.
>
> The new IBM tape drives include two ports. But I think that it is only for
> failover. And I suspect that the support would only be in the IBM tape
> driver. Which  was released with it's source code the last I looked.
>
> I also suspect that you do not need multi-pathing to feed the tape drives.
>  The  native speed for  a lto-5 tape drive is greater than that of a gige
> card. And if you send data that can be compressed 2-1 or 3-1 then  even
> more so.
>
> The hard part is getting the data off the disk fast enough to drive the
> tape drive.

We have sixteen LTO-4 drives that we want to drive with as few media
servers as possible for support reasons. If we could get a few servers
with 10 GigE and and multiple HBAs (or a single multiport HBA), then we
could (attempt) saturating the 10 GigE and having 8 or 12 Gbps of FC on
the other end going to multiple drives in a library.

If multi-pathing is not supported, another option would be to configure FC
zone such that: drives 0-3 are only visible to HBA0-port0, drives 4-7
visible to HBA0-port1, drives 8-11 visible to HBA1-port0, and drives 12-15
visible to HBA1-port1.

We'd prefer to have "normal" multi-pathing if possible, but spreading the
tapes to different HBA ports is another possibility.

We're not concerned with multi-pathing on the drives, but utilizing as
much bandwidth from the clients to the media server, and from the media
server to the library/drives.

_______________________________________________
Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu