We use SAN attached disk at my shop. I should refrain from indicating which vendor (in this context) because I should not convey some kind endorsement. We do not presently use SAN attached tape nor CD or DVD.
The devices are connected via switched fabric (yet another vendor used for the switches), both production and dev/test. The production volumes are replicated to secondary copies for disaster recovery. (dev/test vols are not replicated) The production volumes are in demand 24x7 so we lean heavily on the dual path capability: When one path is taken down either for service or because of an error the other carries the traffic. (This is a customer-facing workload.) Once things are configured, they run without problems. If you are using SLES 10, you will want to be on SP2 for improved SCSI stack behavior. We encountered periodic filesystem errors resulting in some filesystems being switched read-only (to prevent damage) on both VMware hosted i386 and x86_64 and z/VM hosted s390x Linux guests with SLES 10 SP1. (I cannot report on this problem on RHEL. Not enough data there.) I STRONGLY RECOMMEND that people considering SAN look into EDEV where z/VM will present SAN disks as 9336 equivalent FBA DASD. This allows the storage to be managed via the CP Directory, so that your SAN backed storage can be managed as effectively as your ECKD backed storage. We could not take this route initially because at the time EDEV lacked dynamic path controls (presently an open req with IBM). As a result, we plug our Linux guests directly into the fabric. This has some value points, notably reduced I/O overhead, but presents a serious storage management burden. Vendors: Mixed IPL from installation media would be nice. What I mean is, if a disk is attached via SAN, support the SAN IPL method, obviously. But if a disk is attached via EDEV, also support the DASD IPL method. The two should coexist quite well on any CD or DVD. Clearly the 'zipl' bootstrap already contains everything that is needed. Using an ISO 9660 filesystem gives ample room for the bootstrap. -- Rick; <>< On Tue, Jul 7, 2009 at 09:34, Thorsten Diehl<[email protected]> wrote: > Hi all, > > I'm curious and would like to know, who is using zfcp attached SCSI > devices. > If you like, please answer the following questions: > 1. Type (Manufacturer/Model) of the SAN Gateway/Bridge > 2. Category, Type and number of attached SCSI devices (e.g. SCSI Tapes, > DVD drives, disks) > 3. Your experience with the SAN gateway (configuration, reliability) > 4. How often do you use the attached devices (daily, rarely, ....) and > for which purpose > > Authentic example: > 1. IBM 2108-G07 SAN gateway (aka PATHLIGHT) > 2. 1x SCSI-DVD-ROM, 1x IDE-DVD-Multiburner via IDE-SCSI-Converter, 1x > 4mm DDS3 SCSI Tape > 3. easy to configure, runs without problems > 4. regularly, for system z Linux installations via SCSI DVD (no ftp > server required). > > Thanks in advance for your response! > > -- > With kind regards > Thorsten Diehl > > System Test Linux on System z > > IBM Deutschland Research & Development GmbH > Vorsitzender des Aufsichtsrats: Martin Jetter > Geschaeftsfuehrung: Erich Baier > Sitz der Gesellschaft: Boeblingen > Registergericht: Amtsgericht Stuttgart, HRB 243294 > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO LINUX-390 or > visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
