Date: Tue, 23 Mar 1999 14:04:50 +0100 (CET) From: Torbjorn Lindgren <tl@fairplay.no> To: aic7xxx@FreeBSD.ORG Subject: Re: SOFTWARE-RAID-TIPS (was: Adaptec 7890 and RAID portIII RAID controller Linux Support) Message-ID: <Pine.LNX.4.04.9903231310350.783-100000@dahlin.fairplay.no> In-Reply-To: <199903230849.AAA00831@frogger.cisco.com>
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On Tue, 23 Mar 1999, Beau James wrote: > --> dump/restore work on entire filesystems below the OS filesystem layer > --> (thus allowing a backup/restore without touching file access or > --> modification times, which is nice). That means it's not easy (or even > --> possible?) to back up less than the entire filesystem. > > Got it. That's a limitation of the Linux port of BSD dump; Solaris > dump accepts file lists which do not have to be complete partitions. > > --> Combined with the fact that dump has no built-in compression > > Though most tape drives have hardware compression these days. > > --> and does > --> not handle multi-volume archives on Linux, it's not the most ideal > --> choice for backing up large RAID filesystems. > > Ouch. I'd not noticed that in the "BUGS" list, and hadn't overflowed > a tape (yet). It's NOT just dump, Amanda for example doesn't support file-systems larger than a single tape either AFAIK (Oh, you could use GNU tar and break it up, but it's still a mess). The most amazing thing is that people actually DEFEND that decision... Admittedly *I* don't think it's a serious backup system, but evidently lots of other people think otherwise, so... (That and the even more painfull dumping disk junk is each more than enough for me to put it into the same category as "dump". It has some benefits over dump, but at least as many drawbacks IMNSHO). > --> large system (the administrators at our other offices work with 120 GB > --> and larger filesystems). 100GB per tape would be a reasonable capacity > --> for me. Unfortunately, 100GB tape equipment is nowhere near reasonable > --> to purchase. > > US$2.5K for 12/24 GB DAT; US$4.5 K for 140/280 GB DLT. But "reasonable" > is in the eye of the buyer, of course. Hmm, is that 140 as in 7*20 (DLT4000) or 4*35 (DLT7000)? (If it's 4*35 I'm pleasantly surprised by the price). Either way it's not a single tape, which was what the original comment was about (unless Quantum has forgot to tell Quantum about it!). AIT-2 (when it becomes available) will push the limit up to 50GB per tape for "reasonable" tape drives, at least I haven't heard of anything larger being available for decent prices. Yeah, there ARE new stuff coming in that range, but AFAIK nothing that is available now. (Quantum Super DLTtape, AIT-3, LTO (Ultrium/Accelis), all seems to be 100+ GB/tape, sometimes up to 500 GB/tape). -- Torbjörn Lindgren Network Manager, FairPlay International AS E-mail: tl@fairplay.no To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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