Re: RAID for dummies
On Thu, Oct 13, 2005 at 11:00:59PM -0400, the unit calling itself Nick Holland wrote: > J Moore wrote: > > On Thu, Oct 13, 2005 at 07:47:48AM -0400, the unit calling itself Nick > > Holland wrote: > > > >>> Not quite sure what point you're trying to make here... are you > >>> advocating that one develop expertise in all areas to become totally > >>> self-sufficient? If so, I suppose you are all at once: thoracic > >>> surgeon, firefighter, psychiatrist, tax lawyer, microbiologist, etc, > >>> etc, etc. > > > >> No, I'm advocating that if you pick of a scalpel, that you understand > >> how to perform surgery on the species you are going to be cutting on. > >> If you pick up a fire hose, you understand what happens when the water > >> hits full pressure. Etc. Taxes? ok, got me there, no one > >> understands tax law. > > > > And I'm suggesting that trying to be an expert in everything is not a > > realistic goal... why pick up a scalpel at all (to "haul your butt out > > of the fire") if your neighbor has invested years in becoming a thoracic > > surgeon? If surgery is required, I would choose to let the experienced > > surgeon haul my butt out of the fire, and concentrate my energy in my > > field of interest. Sorry if I confused you on that point. > > >From your original post, you said you did not desire to become an expert > on RAID. You didn't talk about farming the maintenance of this system > to other people. No - I can't afford to farm it out. Again, the *only* point I was trying to make is that expertise in a particular field is not a necessary condition to benefit from that field. > >> RAID systems in the hands of people who assume "magic will happen" cause > >> massive down-time problems. In the hands of people who know how to do > >> it, yes, good things really can happen. But I doubt there are any truly > >> mindless RAID options available. > > > > Now I'm confused... are you suggesting that the investment required to > > successfully use an ACS-7500 even approaches that required for the > > "do-it-yourself" RAID setup? > > Not at all. << snip >> Thanks - I appreciate your views on that. Jay
Re: RAID for dummies
Quoth J Moore [snip] >And I'm suggesting that trying to be an expert in everything is not a realistic goal... why pick up a scalpel at all (to "haul your butt out of the fire") if your neighbor has invested years in becoming a thoracic surgeon? If surgery is required, I would choose to let the experienced surgeon haul my butt out of the fire, and concentrate my energy in my field of interest. Sorry if I confused you on that point. If my neighbor has invested years in becoming a thoracic surgeon, I still have the problem of knowing that it is his expertise that I need. If I do need his services, how much knowledge of his field should I know for my own protection and so that I can make rational choices? In the case of RAID, just how effective is the magical incantation? Everything I've seen on this list by people who should know (that's the people who have survived disasters rather than wondering what happened to them) indicates that RAID has become a sales gimmick for customers with more dollars than sense, and unless handled extremely carefully is slower, much more likely to fail catestropically, with marginal gain in accessibility. The main problems are in rebuilding a failed disk and in extremely long downtimes while rebuilding. You don't need to be an expert in everything, but you do need to know enough to know when an expert is needed. Anything that claims that no expertise is needed when in fact expertise is needed is no friend.
Re: RAID for dummies
J Moore wrote: > On Thu, Oct 13, 2005 at 07:47:48AM -0400, the unit calling itself Nick > Holland wrote: > >>> Not quite sure what point you're trying to make here... are you >>> advocating that one develop expertise in all areas to become totally >>> self-sufficient? If so, I suppose you are all at once: thoracic >>> surgeon, firefighter, psychiatrist, tax lawyer, microbiologist, etc, >>> etc, etc. > >> No, I'm advocating that if you pick of a scalpel, that you understand >> how to perform surgery on the species you are going to be cutting on. >> If you pick up a fire hose, you understand what happens when the water >> hits full pressure. Etc. Taxes? ok, got me there, no one >> understands tax law. > > And I'm suggesting that trying to be an expert in everything is not a > realistic goal... why pick up a scalpel at all (to "haul your butt out > of the fire") if your neighbor has invested years in becoming a thoracic > surgeon? If surgery is required, I would choose to let the experienced > surgeon haul my butt out of the fire, and concentrate my energy in my > field of interest. Sorry if I confused you on that point. >From your original post, you said you did not desire to become an expert on RAID. You didn't talk about farming the maintenance of this system to other people. >> RAID systems in the hands of people who assume "magic will happen" cause >> massive down-time problems. In the hands of people who know how to do >> it, yes, good things really can happen. But I doubt there are any truly >> mindless RAID options available. > > Now I'm confused... are you suggesting that the investment required to > successfully use an ACS-7500 even approaches that required for the > "do-it-yourself" RAID setup? Not at all. A car with an automatic transmission is much easier to drive than a car with a stick shift. However, without proper training, you can hurt yourself and others with either. The Accusys boxes are very simple, seemingly reliable, but if you don't play with them for a bit and understand how they work, you can still can screw things up. IN FACT, there are so many neat things you can do with the Accusys boxes, you might be tempted to do something silly and wrong, believing that it will save you from everything. If you aren't willing to learn how the thing works, your overall reliability and uptime will probably be better with a single drive, no RAID at all. Sure, the drive could fail, but your recovery options will be very clear and direct. Nick.
Re: RAID for dummies
On Thu, Oct 13, 2005 at 07:47:48AM -0400, the unit calling itself Nick Holland wrote: >> Not quite sure what point you're trying to make here... are you >> advocating that one develop expertise in all areas to become totally >> self-sufficient? If so, I suppose you are all at once: thoracic >> surgeon, firefighter, psychiatrist, tax lawyer, microbiologist, etc, >> etc, etc. > No, I'm advocating that if you pick of a scalpel, that you understand > how to perform surgery on the species you are going to be cutting on. > If you pick up a fire hose, you understand what happens when the water > hits full pressure. Etc. Taxes? ok, got me there, no one > understands tax law. And I'm suggesting that trying to be an expert in everything is not a realistic goal... why pick up a scalpel at all (to "haul your butt out of the fire") if your neighbor has invested years in becoming a thoracic surgeon? If surgery is required, I would choose to let the experienced surgeon haul my butt out of the fire, and concentrate my energy in my field of interest. Sorry if I confused you on that point. > RAID systems in the hands of people who assume "magic will happen" cause > massive down-time problems. In the hands of people who know how to do > it, yes, good things really can happen. But I doubt there are any truly > mindless RAID options available. Now I'm confused... are you suggesting that the investment required to successfully use an ACS-7500 even approaches that required for the "do-it-yourself" RAID setup? V/r, Jay
DRDB (was: RAID for dummies)
On 2005-10-11 23:58:27 +0200, Joachim Schipper wrote: > DRBD is RAID-1, actually (with n-way replication under development last > time I checked). I assume that was just a typo. ;-) I just listend to a talk about v8. Seems quite production ready. :-) You can get 3-way replication with DRDB commercially. Best Martin -- http://www.tm.oneiros.de
Re: RAID for dummies
J Moore wrote: >> Anyway...you HAVE to spend time getting to know whatever RAID solution >> you are using. Practice, practice, practice!!! Try swapping drives -- >> what happens if you swap a drive with a larger drive? smaller drive? >> how does it indicate errors? etc... In short: never trust anyone else >> to haul your butt out of the fire. > > Not quite sure what point you're trying to make here... are you > advocating that one develop expertise in all areas to become totally > self-sufficient? If so, I suppose you are all at once: thoracic surgeon, > firefighter, psychiatrist, tax lawyer, microbiologist, etc, etc, etc. No, I'm advocating that if you pick of a scalpel, that you understand how to perform surgery on the species you are going to be cutting on. If you pick up a fire hose, you understand what happens when the water hits full pressure. Etc. Taxes? ok, got me there, no one understands tax law. If you don't wish to spend time to learn the RAID tool of your choice, do everyone a favor: skip the RAID. Really. It will *cause* more downtime than it will ever save you. Some solutions are pretty easy (the Accusys is up there as one of the easiest, certainly the easiest I have seen and used), but there are still things you should get to know BEFORE an event, not after... RAID systems in the hands of people who assume "magic will happen" cause massive down-time problems. In the hands of people who know how to do it, yes, good things really can happen. But I doubt there are any truly mindless RAID options available. Nick.
Re: RAID for dummies
On Tue, Oct 11, 2005 at 07:11:03AM -0400, the unit calling itself Nick Holland wrote: > > There's only one RAID system that I think is anything close to as simple > as you desire: > ... > > Accusys ACS-7500 or its competitors. > > No equity position in any of them. > > And yes, that's it. :) > > I'll admit to a lot of "sweat equity" in the Accusys ACS7500. I love > the things -- the simplicity, the fact that they usually "just work", etc. Actually, there seem to be three (3) similar offerings: Accusys (http://www.accusys.com.tw/, or http://www.accusysusa.com/index.htm) Accordance (http://www.accordancesystems.com/) ArcoIDE (http://www.arcoide.com/) They all seem to have pretty uninformative or confusing info on their websites, and they all appear to be "hard to find" (in that retailers are few and far between). It's encouraging to hear that you've had a positive experience with the Accusys hardware. > Anyway...you HAVE to spend time getting to know whatever RAID solution > you are using. Practice, practice, practice!!! Try swapping drives -- > what happens if you swap a drive with a larger drive? smaller drive? > how does it indicate errors? etc... In short: never trust anyone else > to haul your butt out of the fire. Not quite sure what point you're trying to make here... are you advocating that one develop expertise in all areas to become totally self-sufficient? If so, I suppose you are all at once: thoracic surgeon, firefighter, psychiatrist, tax lawyer, microbiologist, etc, etc, etc. Jay
Re: RAID for dummies
On Mon, Oct 10, 2005 at 09:50:29PM -0700, the unit calling itself Raymond Lillard wrote: > >I want to set up an OBSD box as a file server for some Windoze boxes. I > >think a RAID 1 setup will provide sufficient reliability - and it > >appears to be the cheapest way to go. > > > >I don't desire to become an expert on RAID, I don't want to spend a lot > >of money, and I'm confused by what I've read on the subject. Here's how > >I'd like it to work: > > > >One of the disks craps out... an alarm goes off... I walk in with a new > >drive, and replace the failed one (hot-swap?)... beeping stops... no > >data is lost, system "heals" itself by taking care of the new drive... > >years pass, and life is good. > > > >Is this feasible - can I remain ignorant of the RAID details and jargon, > >and still benefit from it? > > Ignorance often leads to a very expensive education. I agree - it also leads to off-point drivel > Are you certain that archival backups are not necessary? Certain!? Would you care to point out where I stated or even implied that backups weren't necessary?
Re: RAID for dummies
On Tue, 11 Oct 2005 23:58:27 +0200 Joachim Schipper <[EMAIL PROTECTED]> wrote: > On Tue, Oct 11, 2005 at 08:07:49PM +0100, ed wrote: > > FWIW there is something called DRBD which is considered the closest > > thing to RAID-0 over a network, it can fail sometimes with flaky > > results in testing. I have found it to be troublesom when problems > > occur during sync. > > > > Do you or anyone else know of anything that works better? > > DRBD is RAID-1, actually (with n-way replication under development > last time I checked). I assume that was just a typo. ;-) Yeah was just a brain fart. > I can't say much more. Testing showed that running DRBD is possible > and replication does occur, under fairly non-loaded 'lab' conditions > and only testing failover in case of manually failing drives. However, > I ultimately decided not to pursue DRBD further. > > I haven't looked at AFS too much, but seem to recall not looking into > it further after realizing the Kerberos auth issue you mentioned. AFS client's don't need Kerberos, I think there's some means of turning it off at the bosserver, but I havn't yet got a lab set up just yet, unfortunately AFS demands a lot of setup before you can really know what you're doing. FWIW don't bother getting the Managing Andrew File System book, Esther Filderman does not recommend it, and she's probably the most famous person on the subject. I you know any good distributed file system software let me know please, it's quite a nagging hole for me. -- Regards, Ed http://www.usenix.org.uk
Re: RAID for dummies
On Tue, Oct 11, 2005 at 08:07:49PM +0100, ed wrote: > On Tue, 11 Oct 2005 21:55:30 +1000 > "Rod.. Whitworth" <[EMAIL PROTECTED]> wrote: > > > RAID 1 (or any RAID really) is NOT a backup. It is a high availability > > system. > > High availability does NOT mean never unavailable. > > Hello again Rod, > > I've been looking at ways to make a redundant and load balanced SAN. As > you put it, it's not high reliability, once you get a problem with RAID, > or the box that it's attached to, you can consider the data 'unknown'. > > The best solution that I have seen is, although a bit of overkill, AFS > (Andrew File System). It's kerberos based authentication on a token > basis. Although I have not implemented it I see that it falls short > because the tokens (if used) expire after 10 hours, which might require > a cron job (if that fails does hell break loose?). > > Because it is limited to a single read/write node per volume, I see that > a volume would be required for every directory that might take more than > a few minutes to replicate to the read only nodes to avoid hammering the > read/write node. > > All the other network distributed file systems seem under developed or > unstable. > > FWIW there is something called DRBD which is considered the closest > thing to RAID-0 over a network, it can fail sometimes with flaky results > in testing. I have found it to be troublesom when problems occur during > sync. > > Do you or anyone else know of anything that works better? DRBD is RAID-1, actually (with n-way replication under development last time I checked). I assume that was just a typo. ;-) I can't say much more. Testing showed that running DRBD is possible and replication does occur, under fairly non-loaded 'lab' conditions and only testing failover in case of manually failing drives. However, I ultimately decided not to pursue DRBD further. I haven't looked at AFS too much, but seem to recall not looking into it further after realizing the Kerberos auth issue you mentioned. Joachim
Re: RAID for dummies
From: ed [mailto:[EMAIL PROTECTED] > I've been looking at ways to make a redundant and load > balanced SAN. As > you put it, it's not high reliability, once you get a problem > with RAID, > or the box that it's attached to, you can consider the data 'unknown'. > > The best solution that I have seen is, although a bit of overkill, AFS > (Andrew File System). It's kerberos based authentication on a token > basis. And this is available in OpenBSD: http://www.stacken.kth.se/projekt/arla/ DS
Re: RAID for dummies
On Tue, 11 Oct 2005 21:55:30 +1000 "Rod.. Whitworth" <[EMAIL PROTECTED]> wrote: > RAID 1 (or any RAID really) is NOT a backup. It is a high availability > system. > High availability does NOT mean never unavailable. Hello again Rod, I've been looking at ways to make a redundant and load balanced SAN. As you put it, it's not high reliability, once you get a problem with RAID, or the box that it's attached to, you can consider the data 'unknown'. The best solution that I have seen is, although a bit of overkill, AFS (Andrew File System). It's kerberos based authentication on a token basis. Although I have not implemented it I see that it falls short because the tokens (if used) expire after 10 hours, which might require a cron job (if that fails does hell break loose?). Because it is limited to a single read/write node per volume, I see that a volume would be required for every directory that might take more than a few minutes to replicate to the read only nodes to avoid hammering the read/write node. All the other network distributed file systems seem under developed or unstable. FWIW there is something called DRBD which is considered the closest thing to RAID-0 over a network, it can fail sometimes with flaky results in testing. I have found it to be troublesom when problems occur during sync. Do you or anyone else know of anything that works better? -- Regards, Ed http://www.usenix.org.uk
Re: RAID for dummies
On Mon, 10 Oct 2005, J Moore wrote: > I want to set up an OBSD box as a file server for some Windoze boxes. I > think a RAID 1 setup will provide sufficient reliability - and it > appears to be the cheapest way to go. > Yep, do it all the time. > One of the disks craps out... an alarm goes off... I walk in with a new > drive, and replace the failed one (hot-swap?)... beeping stops... no > data is lost, system "heals" itself by taking care of the new drive... > years pass, and life is good. > If you want good reliability & minimum cost, we use RaidFrame all the time. Only two problems with your scenario: 1) The parity rebuild times can get pretty long (30+ minutes); 2) Your 'alarm' would be the nightly email saying that the drive set did not pass parity check (i.e. not realtime). > Is this feasible - can I remain ignorant of the RAID details and jargon, > and still benefit from it? > If you don't want to use s/w raid, get a BIOS-level like the AccuSys already mentioned. Lee
Re: RAID for dummies
On Tue, 11 Oct 2005 07:11:03 -0400, Nick Holland wrote: >There's only one RAID system that I think is anything close to as simple >as you desire: >... >> Accusys ACS-7500 or its competitors. >> No equity position in any of them. > >And yes, that's it. :) > >I'll admit to a lot of "sweat equity" in the Accusys ACS7500. I love >the things -- the simplicity, the fact that they usually "just work", etc. Very true and for the record (quote me if you like, Nick) I have had my first "voltage excursion failure" involving an Accusys ACS7500.The power surge knocked out the server totally - it would not boot. The client had it delivered to my office where I found it dropping into ddb too early in the boot to be useful. I.e. before the first propeller stopped spinning :-) Splitting the system showed that the ddb crash happened on only one of the two drives. The other was a total disaster. Warranty replacement fixed that one. The other drive was pulled from its tray and inserted into a non-raid tray, jumpered as a slave, in my lab-rat. There I found that /bsd was exactly the correct size but cmp showed it to have two large blocks of nulls where code should be. Every other file passed an MD5 check (well all the ones I thought to include!) Replacing /bsd had the entire system up and running, albeit on one tray. They have another as a quasi backup but wisely they kept it out. using that is a last resort before a restore from the total backup archives. This should be a lesson that: RAID 1 (or any RAID really) is NOT a backup. It is a high availability system. High availability does NOT mean never unavailable. This was an exceptional event and the client is very satisfied with the outcome. The company is a large civil engineering design office so some appreciation of things technical was there to smoothe the process. > >As close as they are to "Just Work"ing, I still felt the following notes >are important: > http://www.holland-consulting.net/tech/acs7500.html > I missed seeing that before but I knew about the management stuff for the 7500. I had meant to hack on it before now but the pathway to Hell is paved with good intentions and I'm still fighting off the alligators in the swamp. I'll file it and I'd advise the same to others. Thanks again, Nick. In the beginning was The Word and The Word was Content-type: text/plain The Word of Rod. Do NOT CC me - I am subscribed to the list. Replies to the sender address will fail except from the list-server.
Re: RAID for dummies
Rod.. Whitworth wrote: > On Mon, 10 Oct 2005 23:09:39 -0500, J Moore wrote: > >>I want to set up an OBSD box as a file server for some Windoze boxes. I >>think a RAID 1 setup will provide sufficient reliability - and it >>appears to be the cheapest way to go. >> >>I don't desire to become an expert on RAID, I don't want to spend a lot >>of money, and I'm confused by what I've read on the subject. Here's how >>I'd like it to work: Danger! Danger! :) >> >>One of the disks craps out... an alarm goes off... I walk in with a new >>drive, and replace the failed one (hot-swap?)... beeping stops... no >>data is lost, system "heals" itself by taking care of the new drive... >>years pass, and life is good. >> >>Is this feasible - can I remain ignorant of the RAID details and jargon, >>and still benefit from it? Well, gee. That sounds like such a reasonable request. For HW RAID, this should be possible, unfortunately, it is rarely that simple. There's only one RAID system that I think is anything close to as simple as you desire: ... > Accusys ACS-7500 or its competitors. > No equity position in any of them. And yes, that's it. :) I'll admit to a lot of "sweat equity" in the Accusys ACS7500. I love the things -- the simplicity, the fact that they usually "just work", etc. As close as they are to "Just Work"ing, I still felt the following notes are important: http://www.holland-consulting.net/tech/acs7500.html I also note that if you google for ACS7500, you end up seeing that page before seeing the Accusys website...their site is really lame. There's some stuff I'm finding burried under the covers of their website...I'll be updating my page sometime soon (hopefully). I've recently found the ACS7500 has a mostly-hidden serial interface and apparently has the ability to be managed/monitored via the ATA interface and that serial interface. That leads to some interesting possibilities (though, at the moment, ONLY possibilities -- there is no OpenBSD support for the ATA-based management at the moment, and the serial interface is mostly undocumented)... I will also (hopefully) be getting an ACS7630 soon, I'm sure I'll have something to say about it when I get it... Anyway...you HAVE to spend time getting to know whatever RAID solution you are using. Practice, practice, practice!!! Try swapping drives -- what happens if you swap a drive with a larger drive? smaller drive? how does it indicate errors? etc... In short: never trust anyone else to haul your butt out of the fire. Nick.
Re: RAID for dummies
On Mon, Oct 10, 2005 at 11:09:39PM -0500, J Moore wrote: > I want to set up an OBSD box as a file server for some Windoze boxes. I > think a RAID 1 setup will provide sufficient reliability - and it > appears to be the cheapest way to go. > > I don't desire to become an expert on RAID, I don't want to spend a lot > of money, and I'm confused by what I've read on the subject. Here's how > I'd like it to work: > > One of the disks craps out... an alarm goes off... I walk in with a new > drive, and replace the failed one (hot-swap?)... beeping stops... no > data is lost, system "heals" itself by taking care of the new drive... > years pass, and life is good. > > Is this feasible - can I remain ignorant of the RAID details and jargon, > and still benefit from it? > > Thanks, > Jay Having just had a - more or less - positive experience with my shiny new (software) RAID-1 over two 'shiny' old, old 4 GB IDE disks I dug out of somewhere on my 'shiny' 'new' PII machine, I can say a couple of things. Note that this is just out of personal experience, this is the first RAID I've ever built outside of testing with two loopback files on Linux, and that I've read TFM a couple of times. In my case, I sat down at the console. I tried to log in, and was greeted by the kernel aborting transactions to the second IDE bus, and very little happening. The system was unresponsive (not totally, but quite annoyingly so) and wouldn't log me in, from what I could guess, from not being able to update logs and wtmp. I powered down, examined the disk, powered up, noticed the second IDE interface was disabled according to dmesg, and was greeted by a flurry of parity rebuild (which failed immediately, unsurprisingly) and fsck messages. After some verification and rebuilding /var/run/ld.so.hints (which, apparently, got hit a little too close by fsck), the machine was back in business. RAID is cool. However, having some technical knowledge is always required. I don't find it overly complex - if you can get to -stable, you can get a (software, never had the chance to tinker with hardware) RAID working. And backups are very, very useful. Even if only because RAID makes you feel slightly too confident, which isn't justified when newfs'ing the wrong partition. (For those interested, the above was set up as a testing box, built out of mostly untrusted components; it managed to compile -stable and a couple of ports, twice, so memory &c seem to be good - but one disk didn't want to work at all, and a second died as described above. Two down, two to go... I'll look at replacement parts. And yes, I newfs'ed the wrong partition. It was late, I knew there was nothing important on the box, and I was pretty confident in the RAID. After newfs'ing /, it was time for a reinstall...) Joachim
Re: RAID for dummies
J Moore wrote: I want to set up an OBSD box as a file server for some Windoze boxes. I think a RAID 1 setup will provide sufficient reliability - and it appears to be the cheapest way to go. I don't desire to become an expert on RAID, I don't want to spend a lot of money, and I'm confused by what I've read on the subject. Here's how I'd like it to work: One of the disks craps out... an alarm goes off... I walk in with a new drive, and replace the failed one (hot-swap?)... beeping stops... no data is lost, system "heals" itself by taking care of the new drive... years pass, and life is good. Is this feasible - can I remain ignorant of the RAID details and jargon, and still benefit from it? Ignorance often leads to a very expensive education. Are you certain that archival backups are not necessary? While a properly designed RAID solution will (may) protect users from loss of data due to h/w failures, it will do nothing to protect them from themselves. Furthermore, off-site backups are needed to recover from catastrophic events, like fire, flood, hurricanes, earthquakes, etc ... I don't know how important the data is, but as the old aphorism goes, "If its important, it's backed up." Regards, Ray
Re: RAID for dummies
On Mon, 10 Oct 2005 23:09:39 -0500, J Moore wrote: >I want to set up an OBSD box as a file server for some Windoze boxes. I >think a RAID 1 setup will provide sufficient reliability - and it >appears to be the cheapest way to go. > >I don't desire to become an expert on RAID, I don't want to spend a lot >of money, and I'm confused by what I've read on the subject. Here's how >I'd like it to work: > >One of the disks craps out... an alarm goes off... I walk in with a new >drive, and replace the failed one (hot-swap?)... beeping stops... no >data is lost, system "heals" itself by taking care of the new drive... >years pass, and life is good. > >Is this feasible - can I remain ignorant of the RAID details and jargon, >and still benefit from it? > >Thanks, >Jay > > Accusys ACS-7500 or its competitors. No equity position in any of them. >From the land "down under": Australia. Do we look from up over? Do NOT CC me - I am subscribed to the list. Replies to the sender address will fail except from the list-server.
RAID for dummies
I want to set up an OBSD box as a file server for some Windoze boxes. I think a RAID 1 setup will provide sufficient reliability - and it appears to be the cheapest way to go. I don't desire to become an expert on RAID, I don't want to spend a lot of money, and I'm confused by what I've read on the subject. Here's how I'd like it to work: One of the disks craps out... an alarm goes off... I walk in with a new drive, and replace the failed one (hot-swap?)... beeping stops... no data is lost, system "heals" itself by taking care of the new drive... years pass, and life is good. Is this feasible - can I remain ignorant of the RAID details and jargon, and still benefit from it? Thanks, Jay
