Date: Sun, 30 May 1999 04:02:53 -0400 From: Leo Papandreou <leo@talcom.net> To: questions@freebsd.org Subject: Re: RAID: How does it work? (clueless about RAID) Message-ID: <19990530040253.A13440@homer.talcom.net> In-Reply-To: <Pine.BSF.3.91.990529204057.17456A-100000@dsinw.com>; from rick hamell on Sat, May 29, 1999 at 08:49:54PM -0700 References: <3.0.6.32.19990529201736.007a4bb0@we.mediaone.net> <Pine.BSF.3.91.990529204057.17456A-100000@dsinw.com>
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On Sat, May 29, 1999 at 08:49:54PM -0700, rick hamell wrote: > > > What I've understood until now, RAID 5 is a multiple disk array which acts > > like one big disk, and the data is scattered throughout the disks. Am I > > right, or completely wrong? > > There are different types of RAID. RAID 0 through RAID 5. I wish > I could find my referances on this but what I remeber is that each level > could be a combination of software or hardware, with RAID 5 being the www.dpt.com has a technical library section that's quite good. > most fault-tolerant (and expensive,) while RAID 0 is the least. > > > Okay, say if I was going to build a mega WebServer using FreeBSD and I > > wanted to utilize RAID 5 for data protection and stuff. I'm sure first I'd > > need a SCSI adapter. Does it have to be a special one? When I install For hardware RAID you need a RAID controller somewhere in the scsi chain. > > FreeBSD how does it know that I'm using RAID 5? The file system code doesnt. As you've pointed out, RAID makes your disks appear as one disk. If the controller sits in a PCI slot, the driver will know about it, of course. Even that isnt the case if you are using a scsi-scsi raid setup. > Is that something that I > > set in the SCSI BIOS or something. > > It depends on what level of protection you want and can afford. > Around my office we simply do dual SCSI controllers with mirrored drives > in hot swappable drive bays. We don't need the protection a full RAID 5 > system. I personally think this is the kind of solution you should look > at for a simple web server. > > > I really need a RAID tutorial, because I'm making things move and groove at > > my workplace. We'll be needing a WebServer soon, and I want to make sure > > it's stable and that my data is safe. > > > > Also, any suggestions on good tape backup drives? > > Make a back-up server. I've never been a fan of tape backups, way Please believe me when I tell you that you need a tape backup :-) If your data is valuable to you, back it up and lock the tapes in a completely different location than the server. > to many things can go wrong for reliable protection. You could have two > load sharing servers, if one goes down the other one takes everything > over. That way you wouldn't be down at all, simply running slower. :) That's a nice setup, but it isnt a backup sol'n. > > Rick > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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