John R Pierce wrote:
> absolutely CRITICAL to any SAN implementations is that the storage
> controller (iscsi target, be it openfiler or what) remain 100% rock
> solid tsable at all times.
>
> you can NOT REboot a shared storage controller without shutting all
> client systems down first (or at least unmounting all SAN volumes)
>
> its non-trivial to implement a high availability (active/standby)
> storage controller with iscsi. very hard, in fact.
>
>
Dell have recently announced a product that may help a lot with this
they call it Virtualized ISCSI devices see
http://www.cns-service.com/equallogic/pdfs/WP910_Virtualized_iSCSI_SANs.pdf
> commercial SANs are fully redundant, with redundant fiberchannel cards
> on each client and storage controller, redundant fiberchannel switches,
> redundant paths from the storage controllers to the actual drive arrays,
> etc. many of them shadow the writeback cache storage so if one
> controller fails the other one has any write cached blocks and can post
> them to the disk spindles transparently to maintain complete data
> coherency. Trying to achieve this level of 0.99999 uptime/reliability
> with commodity hardware and software is not easy.
>
>
>
>
> _______________________________________________
> CentOS mailing list
> CentOS@xxxxxxxxxx
> http://lists.centos.org/mailman/listinfo/centos
>
>
_______________________________________________
CentOS mailing list
CentOS@xxxxxxxxxx
http://lists.centos.org/mailman/listinfo/centos
