SN-5428-2-K9

darkfader · ‎03-03-2008

Hi,

i assume for many of you this old box will seem a ghost from the past.

i opted for these models for building a small fc+iscsi based SAN with a very (i mean it) small budget. I have one of these right now and am testing wheter it will do all we need or not.

The san is supposed to attach 2-4 XenEnterprise hosts to two EMC^2 CX600 storage systems, and for now I have to go via iSCSI as the software vendor only supports software iSCSI as clustered storage. Later on I'm planning to attach the host systems via FC and use iSCSI for our lower-bandwidth systems.

I've read the configuration guide and also all SN54xx related posts in here, but still i'm left with a few basic questions. (My imppression is that the config guide does not really bother with SAN-related tasks, reminds me of the last time i set up a more current MDS...)

In the current setup I just have one node attached to on the CX' SPs via iSCSI. It's tested that far, I/O peak throughput at around 93MB/s is giving me much hope.

anyway:

One post in here says that the SN4528 can only inherit san zoning information from another switch via an E-Port. Is this true? And how does this relate to ZoneSets defined in the switch? Are they "iscsi-fc zonesets" but not FC zones as in normal zoning?

Another post said that clustered SN54xx will go dead if the backend storage uses same port WWNs in active/active mode. first of all, if thats true, then it's a sad joke. :(

Luckily, our EMC^2 boxes can't handle active/active mode anyway.

Still I'm a bit worried about what is going to happen, when i plug each of them into both switches. I hope you agree that that is pretty much standard, but will SN5428 cluster really work with it?

Are there any limits regarding ISL?

If possible I would want to connect both switches over 2x2Gbps ports.

I read something about using an FCIP port to do HA, but somehow this smells weird, donating a gigE interface (and redundancy) to get half the bandwidth. If it needs be :>

Also, in case anyone still remembers:

The manual sometimes addresses both "transparent scsi routing" and "scsi routing" modes by "scsi routing" - on the other hand it stats that HA Mode will only work in "scsi routing" mode. This very much affects the way I have to layout my actual storage, can one of you enlighten me if it is possible to use a HA setup in "transparent scsi routing" mode or not?

also i'm still puzzled how the SN5428 detects new storage devices - I found that my device probably has no scsi-target autopoll set, but I'm not sure this is the issue. Right now it won't pick up storage changes except through a reboot. How this can be a default is beyond me.

Last, is the SN5428 supported in Cisco Fabric and/or device manager in case we add more Cisco devices?

Allow me a little rant: while liking the added management and security features, both the old and current cisco switches I set up are so twisted that I deem buying more quite unfeasable. Just imagine if you bought a 2800 router and 99% of the manual deals not with router functions but with how to attach and manage USB disks. :))

Anyway, I'll keep trying and hope a few more weekends from now I'll have the fully redundant iSCSI setup I want.

florian

colin.mcnamara · ‎03-03-2008

While I applaud your gusto, this product is past end of sale, and nearing end of support. While i understand the focus on putting in a low cost storage network, might I recommend going with 9214's. They are very low cost, allow you to pay per port when you grow, and are very fast (san on a chip infrastructure on the backend). You will not be able to support ISCSI at first, but you will have a thousand times less headaches then putting in a old device that is reaching the end of its useful lifespan.

If you desperately needed ISCSI and had a shoestring budget then you could always throw up a pair of ISCSI Enterprise Target Daemon head ends (linux iscsi head) backed into two 9124's.

Please reference the milestone dates for the SN5428 in the following.

http://www.cisco.com/en/US/prod/collateral/ps4159/ps6410/ps2160/prod_end-of-life_notice0900aecd801e3d1c.html

darkfader · ‎03-03-2008

hi Colin,

I'm very much aware of the last support dates for the SN5428 :(

- a 9124 runs about four times the SN5428 price, assuming both are used.

- if it doesn't even do iSCSI (due to that silly vendor I really do need iSCSI even if it's just for like a year till they finally offer direct FC attachment) I could as well grab two brocade/mcdata, use inferior :> port zoning and be done with the whole setup in an hour.

- using linux enterprise target would need additional hardware which will most probably sport higher failover times than the SN5428 plus I'll put the time I save by not messing with the router into setting up a proper HA solution on linux.

also, I maintain 50ish san-attached linux hosts and feel safe saying that it's not really that much reliable in the storage stuff :))

the obvious point might be to simply not use Citrix XenEnterprise but use RHEL and GPFS directly attached.

thank you for the input anyway. I plan two things for tomorrow:

- attach the second storage processor to the SN5428 and try a little basic failover test

- have a beer and rethink options

Regards,

Florian

dmcloon · ‎03-03-2008

Hi Florian,

We will support the SN5428 until June 2010. In each TAC we still have a few old timers that know SN5428 so there should be no problem getting support, but bear in mind any new bugs found will NOT be fixed. For any h/w replacement your SN5428 serial number must already be covered under an existing Cisco support contract. We stopped cutting new h/w support contracts for SN5428 on June 30, 2006. It would be risky to proceed with SN5428 deployment if you have no existing h/w contract. How would you ever get a replacement ?

Regarding your CX600, the SN5428 does know how to send an EMC proprietry trespass command to force a LUN failover from a failed SP to the active SP.

The SN5428 contains an embedded FC switch. It supports standard pwwn based zoning. You can ISL two SN5428 together with one or more FC links (no need for FCIP) and an SN5428 will appear in Fabric Manager discovery map, but you cannot manage a SN5428 from FM. In a pure SN5428 topology (no MDS) you would need to zone via the SN5428 web gui or CLI. You could deploy the SN5428s as just a pair of FC switches and connect FC hosts and CX600 to the SN5428 FC ports. Or you can simultaneously run SN5428 as an iSCSI gateway for iSCSI hosts and FC switch for FC hosts, but also remember there is no need to do iSCSI on SN5428 if the CX600 natively supports iSCSI, as some Clariions do.

With SN5428 SCSI Routing mode the CX600 would see all iSCSI hosts sharing the same pWWN. The LUN access for all iSCSI hosts using SN5428 as a gateway would be controlled by LUN mappings configured in the SN5428 rather than the storage array (via Navisphere). In SCSI Routing mode you can still implement standard FC zoning on the switch portion of the SN5428. For the FC hosts LUN access would be controlled by Navisphere like a regular SAN, as each FC host would individually known to the CX600 in it's "Connectivity Status" view.

Cheers

Dallas

Sydney TAC