On Sat, Jul 11, 2009 at 04:40:02PM -0600, lee wrote: > On Fri, Jul 10, 2009 at 07:04:26AM +1000, Alex Samad wrote: > > > comes down to how much you value your data. > > It comes down to how much money you can spend on securing it. just about the same thing > > > My home server has 10 x 1T drives in it a mix of raid1 + raid5 + > > raid6, I have a second server with 9 x 1T drives in it (in the > > garage) to do my backups - because it would take too long to send > > off site and I don't want to spend money on a tape system - i value > > my data - well I could afford to throw money at the problem. But I > > have some important info there, photos & video of my daughter etc > > ... > > Well, that's like $3000+ you spent on the drives alone, plus about > another $2000 or so for the controller cards. About $8k in total? Then > replace at least the disks about every three years. I don't have that > kind of money (and not that much data). And the more drives you have, > the more disks can fail. Umm 1TB @ $115 = ~$2K motherboard with 6 sata ~$200 + 2 x Adaptec SATA controllers ~$120 each The drives were expensive yeap, but I have that much stuff (well once you take out the backup server so 10 drivees and then raid6 - another 2 drives = ~8Tb worth of data which really equates to about 6T of data to leave some head room) so roughly ~$3K (aus dollars) > > > > I'm not afraid of that. But the point remains that having less md > > > devices reduces the chances that something goes wrong with their > > > discovery. The point remains that reducing the complexity of a setup > > > makes it easier to handle it (unless you reduced the complexity too > > > much). > > > > Ok to take this analogy even further why have 1T drives, why not stick > > with 1G hard drives - less data less chance of errors. > > Yes --- but you probably have a given amount of data to store. In any > case, the more complexity your solution to store the data involves, > the better the chances are that something goes wrong. That can be > hardware or software as well as the user making a mistake. The more > complex a system is a user is dealing with, the easier it is to make a > mistake --- and software or hardware you are not using can't give you > problems. yes > > > If you are building a large system or !!complex!! system, bit of > > planning before hand, I set mine up and haven't had a problem with md, I > > have lost some drives during the life of this server - the hardest thing > > is matching drive letter to physical drive - I didn't attach them in > > incremental order to the mother board (silly me) > > Yeah, I know what you mean. The cables should all be labeled and > things like that ... it all about making assumption we do it all the time, based on our previous experiences. > > > > There's nothing on /etc that isn't replaceable. It's nice not to lose > > > it, but it doesn't really matter. If I lost my data of the last 15 > > > years, I would have a few problems --- not unsolvable ones, I guess, > > > but it would be utterly inconvenient. Besides that, a lot of that data > > > is irreplaceable. That's what I call I a loss. Considering that, who > > > cares about /etc? > > > > really what about all your certificates in /etc/ssl, or your machines > > ssh keys, > > There are certificates and ssh keys? I didn't put any there. You don't run any https site nor use ldaps or ssl postgress connections. I think you will find you system ssh keys are there :) > > > or all that configuration information for your system mail, > > ldap, userids, passwords, apache setup, postgress setup. > > It's easy to keep a copy of the configuration file of the mail server > on the /home partition --- and it's easy to re-create. There are only > two userids, no ldap, no postgres, and the config for apache is > totally messed up on Debian anyway since they split up the config file > so that nobody can get an idea how it's configured. > > Anyway, you can always have backups of /etc; it's not changing very > frequently like /home. > > > Admittedly you could re create these from memory but, there are some > > things that you can't > > If you have data like that on /etc, you need a backup. I would say that you are very lucky to not have to backup your /etc > > > > What I was wondering about is what the advantage is of partitioning > > > the disks and creating RAIDs from the partitions vs. creating a RAID > > > from whole disks and partitioning the RAID? > > > > I have to admit I have evaluated partitioning + raid v's raid + > > partitioning, I think I would go with the previous, more system (old > > linux box, windows boxes, mac boxes ) understand partitions - where as > > not all OS understand raid + partitioning. And currently I don't see the > > advantage to raid + partitioning > > Hm, is it possible to read/use a partition/file system that is part of > a software-RAID without the RAID-software? In that case, I could see > how it can be an advantage to use partitions+RAID rather than > RAID+partitions. But even then, can the "other systems" you're listing > handle ext4fs? I still don't see the advantage of partitioning+RAID. with raid you can mount the single partition and use it as is if you want, but I would suggest to only do that in emergancies > > > I believe the complexity is not that high and the returns are worth it, > > I haven't lost any information that I have had protected in a long time. > > Maybe that's because we made different experiences ... To give an > example: I've had disks disconnecting every now and then that were > part of a RAID. The two disks were partitioned, RAID-1s created from > the partitions. Every time a disk would lose contact, I had to > manually re-add all the partitions after I turned the computer off and > back on and the disk came back. I have had faulty hardware - I got it fixed > > Since there were three partitions and three md devices involved, I > could have made a mistake each time I re-added the partitions to the > RAID by specifying the wrong partition or md device. if you did it on such a regular basis why not write a script ? > > Now having only one md device instead of three doesn't offer that kind > of chance to get it wrong. If one disk would be missing, there's only > one disk I could add, and I don't have to worry at all about assigning > the right partitions to the right md devices. true > > To me, that is already an advatage of RAID+partitions. It may be a > small improvement, but things like that can add up. It's just so much > easier to maintain X simple things than it is to maintain X complex > things which provide the same functionality. The day might come where > two or three complex things go wrong at the same time and overwhelm > you with their complexity while you could have fixed them easily if > you had used simpler solutions. raid is not a backup solution. there is always a chance !!something!! might go wrong, I have tried to reduce that by having my !!complex(i diss agree that it is)!! solution with a backup server to reduce the chance of me loosing my vital stuff, for my really important data I also copy to a server off site. > > > true, which is why I throw the book away and try different things some > > times, always good to learn new stuff > > Hehe, try RAID+partitions ;) for now I still don't see any benefit, but at least I know about that option for now > > -- BOFH excuse #405: Sysadmins unavailable because they are in a meeting talking about why they are unavailable so much.
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