Date: Mon, 15 Jul 2002 22:15:38 -0700 From: Glen Mehn <glen@burningman.com> To: freebsd-stable@freebsd.org Subject: Re: Poor Mans Software raid 1 on root partition? Message-ID: <3D33ABFA.3090408@burningman.com> References: <25f401c228d4$a3482fb0$1a01000a@area51><20020711091015.B51520@flake.decibel.org><20020711200902.3653b534.steve@sohara.org><20020713032546.GD61459@wantadilla.lemis.com><20020713075109.06ecf02f.steve@sohara.org><20020713100218.B284@twincat.vladsempire.net><20020713222745.00281f72.steve@sohara.org><20020714004247.GB16279@wantadilla.lemis.com> <20020714071524.1587f419.steve@sohara.org> <007801c22c6c$9dc32fe0$0900a8c0@P1200n> <3D338329.4010205@quack.kfu.com>
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You can get a 3ware 7210 for $120: http://newegg.com it'll save you a lOT of time and heartache, and it's not that much $$... -g Nick Sayer wrote: > It would be far, far better to simply do a daily backup using 'dump'. > For just a little more money than buying a whole 'nother drive, you > could buy a tape drive. Tape drives are really ideal for backups because > you can store the media other than inside the machine you're backing > up. :-) > > If you don't want a tape drive, it's still a better idea to do dumps to > another disk rather than dd. Why? > > 1. You can compress the output of dump. > > 2. You don't have to have identically partitioned disks > > 3. You won't get a "clean" filesystem copying it with dd. In fact, the > source filesystem may change enough over the course of the dd that the > resulting image may be completely useless. > > 4. You can potentially store many, many days worth of backups on the > alternate drive. This lets you restore not just last night's backup, but > potentially last *week's*. > > 5. You can use the 'nodump' flag (see chflags(1)) to exclude files from > the backup that are uninteresting. > > Yes, doing a restore takes a little more time than simply booting the > other drive. But in practice, the likelyhood that you will really *need* > to do so is sufficiently low as to not be worthwhile, IMHO. > > The only reason to consider software raid for a truly mission critical > application is if you've got a really large dataset in an external box > that you can move from one machine to another if you need to get back up > quickly. In that circumstance, presumably the contents of the system > disk of the machine don't matter, meaning that the application would > come back on line simply by moving the disk to another machine and > restarting it. If that's unreasonable, then the whole machine requires > RAID (among other things), which means you'll be getting a hardware RAID. > > But don't ever forget that RAID won't help you if you accidently do an > rm -rf / as root. :-) Data integrity is NOT a substitute for good backups. > > Tortise@Paradise wrote: > >> Reading this thread it seems that this is currently not an option. >> >> However why can't we do a poor mans RAID, namely run a cron job say daily >> (or whenever) which bulk copies / updates one (complete) HDD onto a >> second >> one, be it SCSI or IDE, with a view that should the main HDD fail the >> second >> can still be booted from and the only data loss will be the interim since >> the last "backup". Comments on this strategy would be appreciated. >> (No! I >> do not work for a HDD manufacturer.....LOL) >> >> David Hingston MB ChB MBA >> _________________________________________________________________________ >> tortoise@paradise.net.nz >> http://hingston.yi.org/ >> http://pcmc.yi.org/ >> If you seek a digitally signed response please advise. >> If you received a warning on reading this e-mail, please go to >> http://www.baycorpid.com/settings/email.asp?CA=healthcert to update your >> settings >> >> >> >> To Unsubscribe: send mail to majordomo@FreeBSD.org >> with "unsubscribe freebsd-stable" in the body of the message > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-stable" in the body of the message -- Glen Mehn glen at burningman dot com at zerowaitstate dot com at doofdoof dot com "If u ever devour the universe, remember to spit the dragon back out.xx." -swan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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