Although i didnt post much about hardware specifics, i am a nexenta newb in the same boat:

http://nexentastor.org/boards/2/topics/3820

We are probably going with 2 supermicro 2U's for HA connected to two supermicro JBODS.

Intel 10gbe NIC's

Mirroring 2 STEC's for ZIL just seems too pricey for me so we are evaluating cheaper SSD's.

If you havent already, i would go to the HSL list @ Nexenta and see what your options are:

http://www.nexenta.com/corp/supported-hardware/hardware-supported-list

As for what hardware will get you what performance, im still sourcing that out as well.

The thing with the slc ssd is that they last longer. zil is a write heavy operation and the slc's work better with write. in looking at the cheaper ssd's., you may have to replace them sooner, which typical makes it not worthwhile for zil.

The zil space is really necessary for nfs performance. nfs is all sync traffic and the zil will ack the writes.

I think that we typically recommend sas drives over sata, because of the bus structure. sata can lock the bus and decrease overall performance.

We are just in the process of posting the presentations from the openstorage summit and there is a nice session from richard elling on perf considerations. You might want to take a look at that prior to final decision.

Thanks for the responses guys,

Regarding the SLC ZIL ssd ... since size isn't a big consideration; seems like the only 2 real choices are the X25E or STec ZeusRAM ... am I missing any?

Anyone using the Intel 311 20GB Model for their ZIL?

Took a look at the HCL - and had a quick question regarding the Toshiba drives. Since the 600GB is certified, one would assume I would have no issues with the Toshiba 450GB (MBF2450RC)?

Regarding ZIL, i too noticed the X25E's, obviously, MUCH cheaper than a STEC. anyone where have personal experience using the X25E for zil?

In one of the forums it says do not use the X25E with a SAS expander, but the latest HCL pdf says its ok to use X25E with a expander. So im assuming HCL is the one to go with.

shrug

the expanders tend to add latency so we typically recommend having them on a direct bus. It's ok, but not best practice.

Linda, what would best practice be for ZIL in a two node cluster if SSD shouldnt be in the JBOD?

Do you just have one ZIL SSD on the primary node on a direct bus?

Please let us know, Thanks!

yes the zil device needs to be in the jbod for cluster. I guess i was just commenting on best practices. The problem with best practices is that they aren't always the same for every architecture. If it is possible to have it on the system side of the expander than great, if it is not possible(for ha) then it needs to be off the expander. Everything is a tradeoff.

You definately want to have the zil device available to both nodes.

I thought that each system for the HA had it's own ZIL connected to the local system bus?

So you would have 4 ZIL's (two mirrored pairs) ...

It's possible just to run 2 for both systems that are connected to the jbod?

Thanks Linda

anything is possible :)

so for the most availability 2 mirrored pairs is best, but.. not always practical. you could just have 1 zil on each array. that way if you have a head failure, there is zil available on each.

what i don't see in your architecture is 2 heads? if you only have 1 head, running mirrored across the arrays would be all you can do. in a highly available architecture you want to make sure you have 2 of everything, in case 1 fails. In a failure scenario if you have 2 heads, 2 arrays and 2 zil, when you are in failure, you end up having one of everything. the second mirrored pair of zil would only provide protection in failure.

For starters ... planning building a single head system that can be easily upgraded to HA.

It's a relief to know that I can spec the first system with a mirrored ZIL, then split it - no need to budget for 4 ZIL's.

Any word on the compatibility of those Toshiba 450GB 2.5" SAS drives (MBF2450RC) ... plan on picking these up quickly (even though not deploying/purchasing the other hardware for a few months), as there are some good web deals currently.

Thanks again!

lemme check

sometimes i read too fast. i just read how you are planning for ha in the future :) i think the way you are are scaling is nice. sometimes it is good to wade in first. you may take a little perf hit by putting the zil devices on the expander, but as long as you know that going in..

i asked around and the informal opinion is you are better off with the STec ZeusRAM.. better reliability.