Date: Thu, 7 Jun 2001 10:23:37 +0200 From: "Achim Patzner" <ap@bnc.net> To: "Michael VanLoon" <MichaelV@EDIFECS.COM> Cc: <hardware@freebsd.org> Subject: RE: Casing wanted Message-ID: <EAELLHHODLNIKKPLOLEMMEEMCCAA.ap@bnc.net> In-Reply-To: <36F7B20351634E4FBFFE6C6A216B30D54C20@ecx1.edifecs.com>
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> > The gods decided that the customer wants to know just how much these > > 3ware controllers will do for them; currently they are in love with an > > MSI dual P3 mainboard, 4 GB of RAM and a Chenbro casing filled with 16 > > RAID disks on two 3ware controllers (80 GB Maxtor giving them about > > 600 GB of mirrored and striped disk space) at a price they wouldn't > > even get half of that space in SCSI disks. Just keep in mind that a > > hardware RAID SCSI controller with 8 channels is _quite_ expensive. > > Agreed it's quite expensive but... with hardware SCSI RAID you get: > > - You don't have all these squirrelly issues you just brought up (cable lengths, etc.) Which is about the only problem I encountered and 3ware just told me (after a direct hit on their long term memory with a hard object) that there are cables up to 70 cm. > - Automatic unattended hardware failover to hot-spare(s) > - Automatic unattended background fill-in of data on failed-in hot spares > while server is live > - Caching controller that does delayed elevator-sorted write-backs, and > read-ahead This is nothing the 3ware controller won't do. > - Better reliability (yes SCSI drives really ARE built better) No. I had 15 IBM DDYS (of 35) failing after less than 12 months and didn't lose a single Maxtor. > - Higher performance (though yes, IDE performance is pretty good) Hm. I've seen people getting 95 MB/s through a 3ware RAID. Don't forget that it got a single channel per disk. All in all this is a reason why they want this machine - they want to compare performance... > - Depending on the controller from 15 to 60 drives per controller Not really. I'm a strong believer in one channel per disk. > - Higher quality cases, hot-swap cartridges, etc. on the market Definitely not. The best hot swap cartridge I've ever seen was an IDE cartridge. I thought someone mixed Dark Vader and the Cylons and turned them into a status display > So it's not like you're paying more for nothing. There are some very > substantial benefits, especially in the reliability/uptime > department when a disk fails -- no need to bring the server down, or > even be there when it swaps in a hot spare and starts using it. Nothing I wouldn't get wit IDE too... > Admittedly the price-per-gigabyte for IDE disks is much better. > But there's a reason they're so cheap. Yes. There are too many people thinking paying the SCSI-fine is a good thing. The IDE disks we're going to use aren't trash. They showed less failures under heavier load and their performance isn't that bad either. The driver won't see single disks, it will see one large volume. > Just some food for thought... I don't have anything against IDE raid, but > when the problem keeps screaming out that it doesn't want you to do that, > then maybe you shouldn't do that. :-) The problem stopped screaming and actually the problem would have been nearly the same with SCSI: Cabling. Although there is a way around that by using FC-AL disks. Noses. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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