On Thursday 27 October 2005 20:59, Allan Wind wrote: >On 2005-10-27T19:33:22-0400, Gene Heskett wrote: >> Our first foray into using a scsi based commercial server resulted in >> its getting converted to ata disks fairly rapidly as the scsi raid >> lost a drive at 2 week intervals. A single big atapi/eide drive >> turned out to be faster, and a heck of a lot more reliable. > >While I feel for you, it's not a good idea to make decisions based on a >single installation. If you have disks dying every 2 weeks, something >else was up. Heat would be my first guess. Seagate, I think, had a >batch of bad SCSI drives recently.
This was back when scsi drives were 8GB max, so quite a bit of water has passed by now. >Sign up for an account on http://www.storagereview.com/ and check out >the reliability survey. > >I have good luck with IBM (2 GB) and Fujitsu (32 GB) SCSI drives, and >had a Quantum (9 GB) die on me. Those 6 & 8GBers were Quantum/Seagates. And. FWIW, the terrabyte arrays? About 120 days old, a pair of them with 1394B interfaces to the outside world, scsi3-320 inside, very well cooled, have each had at least 1 drive failure in that 120 days. 6 drives in the storage array for a panasonic postbox were fairly good, I think we replaced 2 of them in about 8 years of 24/7 usage in our production bay, so that wasn't too bad. Everytime I've dealt with scsi here at home, I've been burnt by short life except for the 1GB seagate hawks, they're hockey pucks, and one Maxtor 7120s (120MB) that after nearly 12 years, finally got to needing a slap in the chops with my hand to get it started. But I could probably hook it back up to my old coco3, give it a hit, and use it till the next shutdown. No surface errors the last time I checked it. But, generally speaking, we've bought into the scsi is better scene several times because the vendor peddling the gear swore on a stack of bibles it was the be-all and end-all of all our problems, and with the exception of the postbox, scsi has been a fscking disaster in a situation where if it sneezes, 75,000 people see it and 3 will send us emails. The only problem we had using ide drives in the commercial servers seemed to be related to an effect known in the audiotape world as multipass erasure, where a spot would start to pixelize on air, and the only cure was to go back to our archive we keep on cdroms (about 1500 of them now) and re-write that spot. But I haven't seen that effect recently, so maybe ide drives are getting better both at error corrections and at bad block housekeeping. The point is that we can lose one of those 200GB drives, run down to Circuit City and grab another, install it, and have the days workload of commercials loaded onto it in about an hour, so we haven't lost that much income if any since we can route the other server and screw with the local upn feed a lot cheaper than we can sit in black during local times for CBS. We've never turned a bad scsi drive around from the warranty in less than 4 days, and that could be several tens of thousands of dollars in time loss for us. So we tend to go with A: what works, and B: what can be fixed the quickest when it doesn't work. Scsi in our extended experience, has come in a distant 2nd place in dependability, a near 2nd place in performance, and a very distant 2nd place in controlling operating costs. >> Ditto here at home, I gave up on scsi tape drives about 18 months ago >> and bought a 200GB atapi/eide drive & setup amanda's virtual tapes on >> it. It has so far, been about 100x more dependable than the scsi tape >> ever was. > >The interface is probably the most reliable thing on a tape drive. Are >you comparing the same drive, same brand but just different interfaces? Nope, cause tape drives tend to only come in scsi. The only exceptions I'm aware of would have been the Travan drives which were available in either. But the drive itself was a piece of warping plastic crap with a lifetime often measured in sub year divisions. We had 5 of them at one time, and 3 years later I had the last one in my office linux box useing it with amanda. When it started making 2 piece tapes out of $48 tapes, it went thump in the bin, less than 4 years old. I understand there was even a floppy interface on some of the lower quality stuff, which might have worked except the drives were even worse trash than the Travans were. >> Now we've gotten into the video server scene, again with the >> recommended terrabyte raid, scsi3-320 or some such based with a 1394B >> (800 megabits/second=100 megabytes) interface to the servers, and >> again scsi is being a problem child with an occasional stutter while >> playing and always a missed first word as it starts. > >1394B -- array --> scsi --> disk? How many disks? Just curious. I >could not get 1394 to work with Linux, and has to use USB for an >external disk for the enclosure that I picked up after much resarch. I could be wrong, but I think that pair of boxes has 6 drives in each one. The scsi3 card is on an internal pci-x bus, so that part should be good. >> Put the same program file on a single internal big atapi/eide drive >> and the performance is 100% reading while writing so we put in 2 >> drives per server. > >If it works for you good, great, it's a cheaper solution. If you >starting pounding if with multiple users, it may not such a good >solution and you may need more than one spindle to handle the load. I >read one of the postgresql lists that IDE drives apparently claim sync >data immediately while SCSI drives are truthful. That makes a >difference when you are concerned about data transactional data. No doubt. But our uses are more like playing 1 or 2, 1 hour mpeged tv shows, while simultainously recording, or copying in which is much quicker, 1 or 2 newer tv shows, plus a random load thats pretty heavy just before and during the news as the individual reporters upload their packages for playback during the newscasts. But those are smallish, rarely over 2 minutes worth of material per package. So that comes in over a gigabit ethernet cable in just a few seconds each. But we do as much or more news in a day as any station thats not an all news format, something in the order of 3.5 + morning cut-ins hrs a day during the week. >> able to find an rsync workalike that does both branches of the apple >> filesystem so that we can fabricate a darned near realtime, live, >> online, redundant backup in case one server chassis should upchuck >> in the middle of a program playback. >> >> If anyone has a clue how we can simulate an rsync run between 2 dual >> g5 servers at 5 minute intervals, we're all ears. > >Suggest you start a new thread on this. > > >/Allan -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) 99.35% setiathome rank, not too shabby for a WV hillbilly Free OpenDocument reader/writer/converter download: http://www.openoffice.org Yahoo.com and AOL/TW attorneys please note, additions to the above message by Gene Heskett are: Copyright 2005 by Maurice Eugene Heskett, all rights reserved. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
