Re: to scsi or not to scsi?
On Wed, Jun 16, 2010 at 4:37 AM, Jeffrey Engle macgu...@gmail.com wrote: ok, new to the scsi thing as you might have guessed. it just seems to me that it's such a yesterday technology, why is it still in big demand? isn't sata better? (yes, I might just learn something here) Jeff I dunno look at this ; http://en.wikipedia.org/wiki/SCSI and then look at the wikiPs for SATA and other interfaces as well as the external drive interface protocols. Then look at costs for modern SCSI drives. And if the prices don't scare you off pay your money and take your choice. SCSI was great for the PCI Macs. But those old drives got behind as things moved ahead. Tiger Direct seems to have sold off the last of their stock months ago. they are getting harder to find. I like the technology but SATA is good enough for end users on a budget. But if you get a deal on working drives and a Mac friendly interface card check your storage needs and alternatives against the cost. Just beware of wear and tear on used drives. -- Adrian D'Alessio aka; Fluxstringer fluxstrin...@gmail.com http://www.flickr.com/photos/fluxstreamcommunication/ http://www.youtube.com/fluxstringer http://www.facebook.com/FluxStringer http://www.linkedin.com/in/fluxstreamcommunications http://flux-influx.blogspot.com/ http://fluxdreams.designbinder.com/ -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: to scsi or not to scsi?
SCSI may be older, but it is built on faster technology. SATA is a bit cheaper and a bit slower. I have the charts on my system. On my PM G4 sawtooth, I have 2 tested drives plugged in. One's a 320GB EDIE plugged in through SCSI through an SCSI to EIDE adapter, and the other is the same version of the HDD, only SATA. Here are the results during file transfer: SCSI Maxed out at 355MB/s SATA Maxed out at 278MB/s Sent from my Power mac G4 Sawtooth. -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: to scsi or not to scsi?
At 9:37 PM -0700 6/15/2010, Jeffrey Engle wrote: ok, new to the scsi thing as you might have guessed. it just seems to me that it's such a yesterday technology, why is it still in big demand? IEEE-1394, aka Firewire, is a subtype of SCSI-3. SCSI-3 SPI, from 2003, btw, does 5120 Mbps (5.1 Gbps). Why nothing newer? Because HD tech hasn't caught up to those speeds yet! Sure, some drives are beginning to fake it with big buffers (caches), but that only improves performance in certain limited situations. isn't sata better? Right tool for the job... It all depends on the application. SATA is a very simple 1:1 interface. SCSI is a more intelligent/robust 1:many interface. Remember that SCSI came from the server world - where you need large numbers of drives, to offer real-time access to gigantic pools of data. In that world, you don't need to access every drive simultaneously with individual dedicated bandwidth. You just need access to any drive, at any time, and can share the available bandwidth. In a desktop/laptop computer, where you only need access to a couple of drives, SATA, like PATA before it, makes good sense. It's cheap, fast, and easy to cable up. Consider tho the cost of all the SATA cards if you wanted to connect more than a couple HDs... FWIW, - Dan. -- - Psychoceramic Emeritus; South Jersey, USA, Earth. -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: to scsi or not to scsi?
On Jun 16, 2010, at 8:15 AM, Dan wrote:
At 9:37 PM -0700 6/15/2010, Jeffrey Engle wrote:
ok, new to the scsi thing as you might have guessed. it just seems to me
that it's such a yesterday technology, why is it still in big demand?
IEEE-1394, aka Firewire, is a subtype of SCSI-3.
SCSI-3 SPI, from 2003, btw, does 5120 Mbps (5.1 Gbps).
Why nothing newer? Because HD tech hasn't caught up to those speeds yet!
Sure, some drives are beginning to fake it with big buffers (caches), but
that only improves performance in certain limited situations.
Actually, in the enterprise world, SCSI has given way to SAS ('Serial Attached
Storage') drives, but improvements in SATA have meant that, except for the most
demanding throughput needs, SATA has the bulk of the market.
Server grade SATA drives are available, and have, at least in our experience,
been pretty reliable. We've lost zero drives in our SAN since we started using
it three years ago, which is a BETTER service record than our old SCSI RAID box.
We still use a SCSI SAN on our Mail server system, but when that gets replaced
we're likely to replace it with a SATA SAN; we just can't justify the cost of a
SAS SAN. Our file servers (now at 6Tb and growing) all use a SATA SAN, and it's
proven very reliable and more than sufficient to keep up with I/O demands.
(and if you're dealing with large amounts of networked file server space, SAN
is head and shoulders ...and torso and hips and knees and ankles...above any
other solution out there. Need more space? add more drives to the SAN box or
buy another box and stuff it fulla drives. expand your volumes on the fly and
suddenly your serves think that their shared volumes are now twice as big...all
live, unless your %...@#!$@# backup software has a hidden 2TB limit for the
volume format that makes you have to nuke the new volume, reformat and restore
from tapefor two days...)
Frankly, I don't see any reason to invest in a SCSI solution on a standalone
system, or even most servers. If a bunch of SCSI drives and the expensive
controller fall into your lap, you'll see improvements in disk IO and if disk
IO is your bottleneck, you'll see an improvement in performance.
If your bottleneck ISN'T disk IO, then you've just invested in a very very
noisy space heater. 15K SCSI drives are hot and loud.
As for connecting a bunch of drives, if you have need of that much storage,
it's cheaper to get a FW800 RAID box and stuff it full of SATA drives letting
the box sort 'em out, or go bigtime, get a Fiber Channel card and connect it to
a SAN, but you're talking $5K minimum for that kinda setup.
If you're editing Ken Burns' latest opus, though, that's a worthwhile
investment.
Just remember with great disk capacity comes great backup needs. We just spent
$18K to upgrade our tape backup systems to (barely) keep up with our ever
increasing file server space; we really need to spend $30K on a disk-disk
system.
--
Bruce Johnson
University of Arizona
College of Pharmacy
Information Technology Group
Institutions do not have opinions, merely customs
--
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Re: to scsi or not to scsi?
Just remember with great disk capacity comes great backup needs. We just spent $18K to upgrade our tape backup systems to (barely) keep up with our ever increasing file server space; we really need to spend $30K on a disk-disk system. When you say tape do you mean magnetic tape? or is that just a term for a backup device, I haven't seen a tape backup for fifteen years even on my CNC equipment because virtually no speed and unreliability. But that may pin me to lack of knowledge too.:-) John Carmonne Yorba Linda USA Sent from my TiBook 500 -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: to scsi or not to scsi?
At 9:32 AM -0700 6/16/2010, Bruce Johnson wrote:
On Jun 16, 2010, at 8:15 AM, Dan wrote:
IEEE-1394, aka Firewire, is a subtype of SCSI-3.
SCSI-3 SPI, from 2003, btw, does 5120 Mbps (5.1 Gbps).
Why nothing newer? Because HD tech hasn't caught up to those
speeds yet! Sure, some drives are beginning to fake it with big
buffers (caches), but that only improves performance in certain
limited situations.
Actually, in the enterprise world, SCSI has given way to SAS
('Serial Attached Storage') drives
SAS is a form of SSA - which is a flavor of SCSI-3. It's ability to
talk to SATA drives is done very eligantly, by encapsulating in SCSI
packets.
heh.
Gotta love that hum of an array of 15Krpm drives.
It takes tintinitis to a whole new level...
- Dan.
--
- Psychoceramic Emeritus; South Jersey, USA, Earth.
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Re: to scsi or not to scsi?
At 10:20 AM -0700 6/16/2010, john CARMONNE wrote: Just remember with great disk capacity comes great backup needs. We just spent $18K to upgrade our tape backup systems to (barely) keep up with our ever increasing file server space; we really need to spend $30K on a disk-disk system. When you say tape do you mean magnetic tape? or is that just a term for a backup device Real tape. A stationwagon full of tapes far exceeds the bandwidth of the Internet and the reliability of every other storage media. Also dirt cheap, per gb. - Dan. -- - Psychoceramic Emeritus; South Jersey, USA, Earth. -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: to scsi or not to scsi?
On Jun 16, 2010, at 10:20 AM, john CARMONNE wrote: Just remember with great disk capacity comes great backup needs. We just spent $18K to upgrade our tape backup systems to (barely) keep up with our ever increasing file server space; we really need to spend $30K on a disk-disk system. When you say tape do you mean magnetic tape? or is that just a term for a backup device, I haven't seen a tape backup for fifteen years even on my CNC equipment because virtually no speed and unreliability. But that may pin me to lack of knowledge too.:-) Brand new HP MSL-2024 LTO-4 cassette tape system, holds 24 LTO-4 tapes capable of holding 1.6TB each (compressed). Backs up ~860 GB/hr. http://tinyurl.com/24vjxsw Tape still rules for backups; when I mentioned Disk-Disk I'm referring to our preferred systemof having another large SAN, backup the production volumes to the backup SAN, and then run the tape backups off of that. Much faster primary backups, sort of like a giant CCC backup, which makes for very fast restores, and keeps the production volumes at maximum availability longer. And then you get into the petabyte territory: http://www.arsc.edu/resources/silo.html -- Bruce Johnson University of Arizona College of Pharmacy Information Technology Group Institutions do not have opinions, merely customs -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: to scsi or not to scsi?
On Wed, Jun 16, 2010 at 12:32 PM, Bruce Johnson john...@pharmacy.arizona.edu wrote: We just spent $18K to upgrade our tape backup systems to (barely) keep up with our ever increasing file server space; we really need to spend $30K on a disk-disk system. I would also be interested in appropriately vague and incomplete details about your tape backup. :-) Just curious. A non-profit I volunteer at has a Windows PC server which is (guessing) around 5 years or so old. I think it has 200 to 400 GB of SCSI attached storage. Like clockwork once a week their office secretary plops in the oldest of box of 5 or so backup tapes and backs up the drives. I believe they have been doing this since they got it. It is likely they have *never* replaced any of the tapes. One of these days those hard drives are going to die and then we'll find out whether or not they have actually backed up their server data. Or not. They have one other firm IT maintenance policy. Never, ever power off the server. Not even to apply Windows security updates. I have tried to warn them. I think the reaction was something along the lines of, H, that doesn't sound good ... OH LOOK! A KITTEN!. What'cha gonna do? So, anyway, I'm curious how folks who might actually want to preserve their data might approach this. ;-) -irrational john -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: to scsi or not to scsi?
On Jun 16, 2010, at 10:52 AM, iJohn wrote: On Wed, Jun 16, 2010 at 12:32 PM, Bruce Johnson john...@pharmacy.arizona.edu wrote: We just spent $18K to upgrade our tape backup systems to (barely) keep up with our ever increasing file server space; we really need to spend $30K on a disk-disk system. I would also be interested in appropriately vague and incomplete details about your tape backup. :-) Just curious. A non-profit I volunteer at has a Windows PC server which is (guessing) around 5 years or so old. I think it has 200 to 400 GB of SCSI attached storage. Like clockwork once a week their office secretary plops in the oldest of box of 5 or so backup tapes and backs up the drives. I believe they have been doing this since they got it. It is likely they have *never* replaced any of the tapes. One of these days those hard drives are going to die and then we'll find out whether or not they have actually backed up their server data. Or not. They have one other firm IT maintenance policy. Never, ever power off the server. Not even to apply Windows security updates. I have tried to warn them. I think the reaction was something along the lines of, H, that doesn't sound good ... OH LOOK! A KITTEN!. What'cha gonna do? So, anyway, I'm curious how folks who might actually want to preserve their data might approach this. ;-) -irrational john Note from the starter of this fine thread: GREAT STUFF!! Jeff:-) -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: to scsi or not to scsi?
On Jun 16, 2010, at 10:52 AM, iJohn wrote: Snip horror story So, anyway, I'm curious how folks who might actually want to preserve their data might approach this. ;-) Well, I learned that lesson WAY back when I first started sysadminning, my own 'My First Server' was a HP/Apollo HPUX box running Sybase database server, and backed up to a 1G DAT drive religiously, using tar. Then one day I accidentally dropped an important database table, and learned the hard way that tar does not back up open files. Like database data files, which are always open while the database is running. As Titus' dad used to say Betcha won't do THAT again! Sadly, this is how most places like this learn the lesson, the hard way. I'd try very hard to prevail upon them to at least invest in new sets of tapes and, suggest, gently that they practice restoring some files from backup, now, while everything is fine, so that they're not doing this for the first time when the system's gone down and people are screaming for their data, pounding on your door with pitchforks and torches. Pitchforks and torches are very distracting and not optimal for learning new things :-) That'll lead them right to the bad tapes, no doubt. -- Bruce Johnson University of Arizona College of Pharmacy Information Technology Group Institutions do not have opinions, merely customs -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: to scsi or not to scsi?
On Wed, Jun 16, 2010 at 2:11 PM, Bruce Johnson john...@pharmacy.arizona.edu wrote: Sadly, this is how most places like this learn the lesson, the hard way. I'd try very hard to prevail upon them to at least invest in new sets of tapes and, suggest, gently that they practice restoring some files from backup, now, while everything is fine, so that they're not doing this for the first time when the system's gone down and people are screaming for their data, pounding on your door with pitchforks and torches. Pitchforks and torches are very distracting and not optimal for learning new things :-) I would but I fear I have no credibility with them. I did try about a year and 1/2 ago to get them to try to make some steps towards more rational sys admin. I thought I had convinced them to reboot the server on a work day when they were routinely closed to the public so they could apply the pending Windows server security updates. However, when the day rolled around I was told the reboot had been vetoed. Why? Well, because of what the young fellow with the BA in Human Resources who had tried to deal with IT stuff had told them before he left for another job. He told them that they should Always leave the server running. Never turn it off. They viewed not rebooting their Windows server as a prudent move that would save them from potential trouble. A Why take the chance? sort of thing. Seriously. I think that they view maintaining computers in much the same way that many of us maintain the plumbing in our homes. Use it but otherwise ignore it until it stops working. Then pay an exorbitant amount of money to a professional to come out on a Sunday and fix it. Will they be pissed when it hits the fan? Sure. But I think this is just how the world works from their perspective. One of those things that like the weather you really can't do much about and just have to live through. As I said, they are a non-profit funded by donations. I hate to see the money wasted. But I also don't know how to reason with people who view maintenance as what you pay someone to fix after you have pushed a system to failure. :-( Oh, well. I digress ... -irrational john -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
to scsi or not to scsi?
ok, new to the scsi thing as you might have guessed. it just seems to me that it's such a yesterday technology, why is it still in big demand? isn't sata better? (yes, I might just learn something here) Jeff -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
Re: to scsi or not to scsi?
On Jun 15, 2010, at 11:37 PM, Jeffrey Engle wrote: ok, new to the scsi thing as you might have guessed. it just seems to me that it's such a yesterday technology, why is it still in big demand? isn't sata better? (yes, I might just learn something here) SCSI HDs are built to industrial standards and have much higher quality bearings and mechanical workings. They also can turn at up to 15,000 RPM. On the down side, they are hot, energy inefficient, and are difficult to configure. SCSI is like a Hummer in a Prius world. -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
