You're the guy with the two disk raid 10, right? That immediately makes my eyebrows furrow. If you have two disks, you may as well make a raid 1 and keep it simple. While JFS is not exactly new, this is foremost a list about mdadm and linux software raid, not necessarily JFS. Now, software raid is a funny thing. Some people love it, some people hate it, and I don't want to be in the same room with either. I've had great experiences with it, on raid sets of up to 56 disks at a time, and generally think it's great. However, like everything else, YOU CAN shoot yourself in the foot. Because it's a layered system, the kernel won't get in your way if you decide to, say, dd the underlying block devices and obliterate the superblock, or what have you. Part of this sounds like you're looking for best practices. I imagine that's why you made a raid 10, and why you're using JFS. It's probably why you've been fiddling around with blockdev --setra and all that too, maybe some elevator tweaks too. Not to get pedantic, but all these techniques and technologies were designed around specific workloads and hardware types. RAID 10 doesn't really win until you have 4 spindles and higher. I have no doubt that JFS is a great file system, but most people on here use ext3/4 and are happy with that too--and probably have more demanding workloads than you. The issue is, you're shooting in the dark unless you really understand what you want to do and why. You also said HTPC. Is this basically a large bucket for videos and other media? Some might say that's not as important to keep online as, say, your email or personal documents. It's your call. You also have to consider what kind of performance you need--you probably won't see a performance increase here because you only have two disks, and for redundancy every write will take place on two disks, and at best, every read will be interleaved. I'm going to go on a limb here and say for anyone (with data they want to preserve), no matter what, backups make sense and are cost effective. I'm going to be crazy and say that there's no reason that someone who thinks they can afford a 8TB disk array and dual SLI video cards, etc, etc, can't also consider some sort of disk or tape backup. Cumbersome? Can be. But having worked with datasets and filesystems that run into the hundreds of terabytes, and having backed them up to tape, it makes sense. If you have something on the order of tens of disks, sure, go ahead, take that next step and back them up somewhere else to another set of disks. If you have more disks, seriously consider tape--in terms of capacity and power consumption (and data integrity), tape wins. This is, of course, only really valid if you've got data worth preserving. And don't even get me started on "silent corruption" and bit rate errors on 2TB drives. But, heh, at least you didn't ask about raid 5 or 6. :) This stuff, when starting out, rewards experimentation, and failures (especially at home--this HTPC is at home, right?) are often great sources for learning. So, good luck! Cheers cc On Sat, Oct 24, 2009 at 5:01 AM, adfas asd <chimera_god@xxxxxxxxx> wrote: > Actually it it your solution which seems best at this point. But I've been testing to see whether anyone else advocates it or another alternative. > > The division is stark; some have been nothing but helpful, while others have done nothing but complain. You are the only one right between. > > > --- On Fri, 10/23/09, Bill Davidsen <davidsen@xxxxxxx> wrote: >> I told him where and how to back up his data for about >> 8-10% of the price he said it would cost. I explained (as >> several other have) why no raid level is the same as a >> backup. >> >> Sorry if that wasn't the thing you wanted to learn, but >> after it has been explained multiple time, it doesn't seem >> to have been sinking in. And clearly didn't this time. I >> won't waste my time trying to educate people here any more. > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Chris Chen <muffaleta@xxxxxxxxx> "The fact that yours is better than anyone else's is not a guarantee that it's any good." -- Seen on a wall -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
