Date: Mon, 14 Jun 1999 13:46:01 -0500 (CDT) From: Joe Greco <jgreco@ns.sol.net> To: freebsd-isp@FreeBSD.ORG Cc: kpielorz@tdx.co.uk, rjebara@palnet.com Subject: Re: Hardware RAID for FreeBSD Message-ID: <199906141846.NAA43719@aurora.sol.net>
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> other than the DPT boards .. have you guys had any > success with other RAID controlers like Adaptec or AMI I was really disappointed with the performance I was getting out of the DPT. It was easy to saturate the poor thing. Further investigation suggests that this is probably because RAID parity calculation is done by the on-board CPU rather than by silicon. Under normal operation, I only need 1 or 2 MB/s writes, but being limited to not much more than that by the DPT would have been very irritating. SCSI-to-SCSI RAID controllers are nicer and the Mylex can be configured from the front panel (as opposed to something like the DPT SmartRAID IV which requires a DOS app). They appear to the OS as an actual storage device, rather than as a number of discrete drives. This means that you can install OS and stuff on them too, because the PC BIOS sees them as a single drive too. da1 at ahc0 bus 0 target 1 lun 0 da1: <MYLEX DAC960SX 61278B5 4332> Fixed Direct Access SCSI-2 device da1: 40.000MB/s transfers (20.000MHz, offset 16, 16bit), Tagged Queueing Enabled da1: 61278MB (125497344 512 byte sectors: 255H 63S/T 7811C) CMD makes a smaller and I believe less expensive unit. If you are less into performance and simply need RAID5 ability, that may be the way to go... it is half-height too, as opposed to the full-height Mylex. However, the CMD unit has some performance limits (#tags, as I recall). The DAC960SX comes in a three-channel config (2 drive, 1 host) with 16MB cache for a bit more than $2K. ... Joe ------------------------------------------------------------------------------- Joe Greco - Systems Administrator jgreco@ns.sol.net Solaria Public Access UNIX - Milwaukee, WI 414/342-4847 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message
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