There are several differences between now and then. Anybody using the software based raid cards, like the cheap promise/highpoint stuff is asking for trouble, no question.
However, vendors have made 24x7 SATA drives available, they're just not the ones you see at the cheapest prices on pricewatch and newegg. But they're there. WD makes 'em, seagate makes 'em, hitachi makes 'em. Look for drives with the "enterprise" classification, which will get you in the right category, drives with RLE or TRLE I believe I've seen it called. read the specs, because it will say if it's designed for 24x7 use. We switched from SCSI to SATA, and have seen no significant difference in reliability, and a whole lot of savings in $'s. But we don't buy the cheapest POS drive at the lowest pricepoint on pricewatch.com either. And we use almost all 3ware RAID cards for both PATA and SATA. Most of our drives are the WD raptors. I am not sure what the "flashing of the bios" issue is, you can flash the chips on SATA, PATA and SCSI drives with the right software and firmware from the vendor, nothing special about the drive itself that makes SCSI magical. Heck, you can get near petabyte storage arrays now from several top vendors, and guess what? Most of them are using SATA. I believe Netapp is using SATA drives in some of their systems, and anybody who knows Netapp knows they don't release anything unless it's solid, and won't damage their reputation. In short, the SCSI is better theory may be true for a short while longer, but is more likely just the result of inertia, and bad experiencese with cheap crappy IDE drives on crappy controllers, not quality components. On Thu, Aug 17, 2006 at 12:55:01AM +0200, Ingo Schwarze wrote: > > We are not stuck on SATA. The whole data directory has ~ 80GB of data > > so PATA would work just as well. > > I fear you missed the point. This is hardly about SATA vs. PATA, > but rather about ATA vs. SCSI. > > If you do really need reliability, you should seriously consider SCSI > RAID. Yes, it definitely is expensive. > > If your budget constrains you to ATA, you should seriously consider > whether you need RAID at all. Even with RAID, you need good, regular > backups. Remember that RAID 1 or 5 is not a backup strategy but just > a tool to minimize downtime in case of failure and to avoid the loss > of data since the last nightly backup. > > Is it really required that you do not loose any data, not even of > one day, in case of the quite rare event of a *sudden* HD death - > remember, most HD failures can be avoided if you watch out for > symptoms occurring prior to failure? Or is it really required > that the disk is back instantly, i.e. do you really lack the time > to manually > > umount /data > sed 's/wd1a/wd2a/' < /etc/fstab > /etc/fstab.new > mv /etc/fstab /etc/fstab.old && mv /etc/fstab.new /etc/fstab > mount /data > > Well, you might need to block logins and kill some user processes > before doing that, but that's the general idea if you have a > nightly clone on a second disk. You can even mount the clone readonly > and tell users about it, in case they mistype rm arguments. > > Let me give an example. For my small LAN of about 15 workstations > and about 30 or 40 regular users, i do not really absolutely need that > kind of reliability - but i thought it might be a good idea to have > RAID 5 in order to be nice to users just in case - and SATA is no > more that expensive and all... > > So about 2 years ago, i got four 160 GB Seagate SATA disks and a cheap > SATA hardware RAID controller. Of course, no SATA disks are designed > or guaranteed for 24/7 operation, but the dealer specifically told me > those would probably stand the strain. In fact, they did not fail. > But... Quite similar Seagate SCSI disks from the same period had > a firmware flaw triggering occasional failure when given certain > SCSI commands in certain combinations. Seagate released a firmware > fix, asking its clients to flash the drive BIOSes. The SATA drive > BIOS is not flashable, and i do not know whether those disks > contain similar bugs. Maybe they do - if so, that might trigger > the Adaptec SATA controller failures. Of course i know my Adaptec > 2410 SA BIOS is flawed in itself, so i'm considering to replace it > by better hardware anyway (LSI Megaraid, whatever). But what if the > disks themselves contain BIOS flaws? Maybe those will confuse the > better controller as well? Who knows... Perhaps i should just use > those SATA disks without RAID, i will probably end up on the same > level of reliability and with much less headaches. > > You see the point? > > I think this whole mess is still the typical difference of SCSI > and ATA. SCSI is designed for reliabily, if it is broken, serious > vendors actually try and fix it, but it is expensive. ATA is > designed to be cheap. You can run a cheap system with a moderate > level of reliabilty using ATA, but don't expect much. > > Yours, > Ingo > > -- > Ingo Schwarze <[EMAIL PROTECTED]> > > > !DSPAM:44e3a6d977361300112376!
