Adam Levin <[email protected]> writes: > I'd like to open a brief discussion on iSCSI. Recently, we've had two > vendors tell us to abandon iSCSI. We're not using it extensively -- just > investigating it for possible use in certain applications in the data > center and remote offices (primarily remote offices).
If I may hijack this thread, I'm quite intrested in iscsi as well, though it sounds like I'm a few notches down from you in terms of cost per gigabyte budget. First, info about me: I don't have much experience at all with iscsi, (I've used fibre-channel, though, prgmr.com ran entirely on 1GB fibre-channel for the first two years or so. Nice. and cheap. and pretty quick. But the cost per gigabyte is quite large, and it's complex that it's really easy for the new guy to take down everything. I've moved entirely to mirrored local storage and I have no regrets. We haven't had data loss due to 'new guy error' since we switched, we've gained a lot in flexibility (we can put one server in its own location without worrying about proximity to a SAN) and we can now afford new parts with warranty. Now, I'm starting to look at software iscsi. I've got 6 of these massive SuperMicro SC833 cases in my front room right now. (3U 8 hot-swap sata bays) Now, my current setup is a dual-socket quad-core opteron with 32GB ram and a mirror of 1TB sata drives. (currently I use the supermicro 1U twin... the a+ board with 16 ram slots each. I reccomend, if that is the sort of thing you need.) I then partition with Xen and rent out the resulting slices. I want to do the same thing with these new cases (8 cores, 32G ram, 2x1TB disk) but then I want to fill the other 6 disk slots with 1.5TB seagates, import them into an OpenSolaris DomU using Xen's pvscsi stuff. With OpenSolaris, I plan to zraid (or 2zraid) it and export over iscsi. (the big driver for zfs is that I want to use cheap crap disks. silent data corruption happens even on good disks, but it happens a lot more on cheap kit. it is my hope that zfs will make up for the quality difference. ) the other unique bits about my situation is that I have more ram than even my most spendy clients who do everything over NetApp SAN. because I use opterons (thus registered ecc, not FBDIMMS) and motherboards with 16 ram slots, my standard setup with 8 cores and 32GB ram sets me back around $2000, so I can throw ram at my storage solution if that will help. (if you don't have enough ram, don't use Xen. Xen is awesome because of it's strong partitioning, but other virtualization solutions are much better at being miserly with RAM. There is a cost to everything, though, and my experience has been that just paying for the ram and using xen is a lot cheaper than using those other solutions, once you count SysAdmin time. Ram is cheap.) The whole thing has got to be cheap. Amazon charges $0.10-$0.13 per gig, so I'd have to charge $0.04-$0.05 per gig or less to compete, so propritary solutions are right out. So yeah. My concern is that the only time I've used software iscsi (granted, this was two years ago over 100M pipes, and I've got gig now) it was pretty much useless due to speed, even compared to old pata drives. I mean, it doesn't need to be super fast, but it needs to be usable. _______________________________________________ Discuss mailing list [email protected] http://lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
