XSan certification necessary or not?

[Guru Evi]

Hi,

We're considering implementing a SAN in order to consolidate our storage (currently several DAS).

I am considered an experienced Mac/Unix/Linux/Windows System Admin with general knowledge of SAN and FibreChannel and excellent (standard Ethernet) network skills. Here are some questions after talking to our Apple SE

- Apple recommends me to get either certified ($2000 + travel) or pay them to do the installation. Is certification really necessary? Do you learn more than what the current documentation provides? Any other benefits? Is installation all that difficult to warrant forking them over $4000?

- Apple recommends also to get XSan support @ $499/license on top of the $499/node license. Is it really necessary? How much do you have to call support on an XSan and if something really bad happens (hosing the metadata) how much can Apple help short of restoring from backup?

- Apple recommends not installing anything on the MDC's (requiring two) other than XSan in order to reduce latency. I can see where this might become an issue in video editing etc. but we're only going to serve ~70 NFS clients over Ethernet a lot of scientific data and home folders. The only XSan clients would be a couple of NFS servers. I would like to use our 2 8-core Nehalem XServe's for both NFS service and XSan MDC's. How much resources does XSan use on such machines? Is it really necessary to buy more servers in order to have an acceptable solution? Currently we're hardly eating 1% of CPU (20% if we're really bad).

- Apple recommends installing all machines with a 4-channel FC HBA @ $900/card. Is it really necessary to install 16 Gbit of FC madness per machine in order to fill a meager 2 Gbit Ethernet line (off course add some overhead).

Our proposed setup:

2gbit ethernet trunk <-> Xserve w/ 4x FC HBA <-> fc switch <-> 4x fc/promise

[JonThompson]

- I did two installations of XSan at my location without Certification. It's doable, but I learned about some issues that I resolved in the second installation. Unfortunately, many of the hangups in XSan are not noticeable until there is a load, and then they require a rebuild of the SAN to remedy.

- Apple support is very helpful if you find an obscure bug that requires a software update, which you might very well considering you are using XSan in ways that most aren't (note I didn't say unsupported, just unconventional, which is essentially how I use it too.) I found one, and fortunately Apple helped me without a contract, but I was also within the first 30 days of a new copy of xsan2.

- My MDC is performing dual duty as a light filemaker server and light FCS. My secondary is a PPC that is backup OD server. It works well, although if I had the $, I would remedy this in a heartbeat. I did expand from two servers to three last year. Before that, I had my fileserver run as backup MDC. It works much better this way.

- Remember, you need to utilize one dedicated ethernet port for metadata, so you only have 1Gb of bandwidth unless you are putting in an ethernet card. As for the 4x4 HBA, list price for the 2x4 HBA is $600 and the 4x4 is $1000. I think for the added $400, another two ports is worth it, especially if you decide to add a FC tape library to your machines.