HP-UX Mirror and remote storages

[Enrico Venturi]

Hello colleagues,
HP-UX Mirror is a suitable tool to create mirrors through local storage devices, i.e. SCSI disks or local Virtual Arrays...

My question is:
Is it able as well to manage mirrors composed by LUNs (Logical Units) exported by Virtual Arrays connected through geographical optical (D-WDM) networks? Is it able, in this case, to manage the possible long term unavailability of one storage if/when the connection is down? Can the Mirror SW recover it?

thanks a lot
Enrico

[Geoff Wild]

You would take a big performance hit going across a WAN....

Hp's Business Copy or EMC's SRDF are the way to go - to copy data between Storage units across WAN's...

Rgds...Geoff

[Enrico Venturi]

You mean:
HP -UX Mirror cannot manage devices over optical networks
or
HP -UX Mirror can manage devices over optical networks but it's very CPU-expensive?

[Bill Hassell]

Mirroring takes place at the driver level and requires real disks, not networked devices like NFS or a NAS array. However, even if the disk is connected as a real disk, the connection must be enormously fast (for networks) in order to prevent complete degradation of your system. Mirroring cannot (and should never) be queued or delayed, so each write must be completed on all mirrors before proceeding to the next write. With typical disks capable of 20-50 MB/sec, you'll need a connection speed of 500-1000 Mbits/sec, two or more of these connections if this is a production system that cannot tolerate down time.

[Enrico Venturi]

The connection bandwidth isn't a problem: we use a D-WDM link.
It's a problem instead the required capability to manage the temporarily unavailability of a networked devices ... what does it happen when the device comes online?