24 Apr
2008
24 Apr
'08
2:34 p.m.
Date: Thu, 24 Apr 2008 14:20:17 -0400
From: "Roy J. Tellason"
I saw some conversation going by in here recently
about Exabyte drives,
only the numbers don't sound anything like what I have, which is marked
"Model: HH CTS". There are all sorts of other numbers on there, for
various aspects of it.
Most Exabyte drives have model numbers of the form 8xxx, from 8000 to
8900, then the "Mammoth" models. The basic early 8200 will hold
about 2.1G on a standard 8mm tape. Later models require different
tapes to take advantage of larger capacities.
Quality of the drives are all over the place, from the built-like-a-
brick-outhouse 8200 and 8500 to the cheap-hunk-of-plastic 8700.
I'm told that these hold 20G on a tape. The guy I
got 'em from
unfortunately doesn't have any tapes to go along with them. One of those
tapes would back up pretty much of what I have on my LAN here, or whole
machines, as they sit. I'm guessing that the interface I'll be looking
at after I take it off of the current mounting plate will be SCSI-wide,
like the CD drives and some of the other stuff I have with it.
I suspect that that's 20G "compressed", which is the equivalent of
"Chinese electric motor horsepower", i.e. extremely optimistic.
Think I can get 'em going under linux? :-)
Sure--just be certain that the SCSI "flavor" matches what you've got
on your controller.
The general idea is that any SCSI tape drive that supports the
standard command set will work with Linux--and probably many other
platforms. It's been too long since I did "anybody's SCSI tape
backup" software, but the only gotchas are packages that use
nonstandard behavior such as read-after-write or strange varieities
of tapemarks. Heck, even the command set for auto-changers is
standard, being applicable to a little magazine that sits in your
tape drive to a bunch of robots crusing racks of 1/2" reel-to-reel
tapes. At least in theory, you can use anything from a 1/2" reel-to-
reel drive to a DLT without changing software.
Most SCSI tape drives feature read-after-write verification, which
puts them way above the garden variety consumer "floppy tapes", most
of which were garbage, IMOHO.
While not as good as DLT, 8mm is head-and-shoulders above 4mm DAT as
concerns reliability. The bottom of the barrel, IMOHO, was the
Datasonix Pereos 2.5mm format.
Cheers,
Chuck
24 Apr
24 Apr
3:07 p.m.
On Thursday 24 April 2008 17:34, Chuck Guzis wrote:
These were a part of an IBM box, SSA? Something like that. LOTS of hard
drives in there, and some sort of a serial link (loop?) to the computer(s).
Might be, might not, I dunno.
The CDROM drives that were in the same box have a pretty standard 68-pin
connector on the back of 'em that looks to be a good match for some of my
host adapters.
Date: Thu, 24
Apr 2008 14:20:17 -0400
From: "Roy J. Tellason"
I saw some conversation going by in here recently about Exabyte drives,
only the numbers don't sound anything like what I have, which is marked
"Model: HH CTS". There are all sorts of other numbers on there, for
various aspects of it.
Most Exabyte drives have model numbers of the form 8xxx, from 8000 to
8900, then the "Mammoth" models. The basic early 8200 will hold
about 2.1G on a standard 8mm tape. Later models require different
tapes to take advantage of larger capacities.
Quality of the drives are all over the place, from the built-like-a-
brick-outhouse 8200 and 8500 to the cheap-hunk-of-plastic 8700. I'm told
that these hold 20G on a tape. The guy I got 'em from
unfortunately doesn't have any tapes to go along with them. One of those
tapes would back up pretty much of what I have on my LAN here, or whole
machines, as they sit. I'm guessing that the interface I'll be looking
at after I take it off of the current mounting plate will be SCSI-wide,
like the CD drives and some of the other stuff I have with it.
I suspect that that's 20G "compressed", which is the equivalent of
"Chinese electric motor horsepower", i.e. extremely optimistic. Think I can
get 'em going under linux? :-)
Sure--just be certain that the SCSI "flavor" matches what you've got
on your controller. The general idea is that any SCSI tape drive that
supports the
standard command set will work with Linux--and probably many other
platforms. It's been too long since I did "anybody's SCSI tape
backup" software, but the only gotchas are packages that use
nonstandard behavior such as read-after-write or strange varieities
of tapemarks. Heck, even the command set for auto-changers is
standard, being applicable to a little magazine that sits in your
tape drive to a bunch of robots crusing racks of 1/2" reel-to-reel
tapes. At least in theory, you can use anything from a 1/2" reel-to-
reel drive to a DLT without changing software.
I have a couple of boxes of assorted tapes, and a changer of some sort would
sure go a long ways toward removing the tedium out of backing up using those.
Biggest ones in the bunch though are about 256MB, if I'm remembering right.
Most SCSI tape drives feature read-after-write
verification, which
puts them way above the garden variety consumer "floppy tapes", most
of which were garbage, IMOHO.
Got a few of those drives around too, and none of them are installed in
anything. And tapes to go with 'em. A Colorado, and a Conner I think.
Maybe another one, I'm not sure.
While not as good as DLT, 8mm is head-and-shoulders
above 4mm DAT as
concerns reliability. The bottom of the barrel, IMOHO, was the
Datasonix Pereos 2.5mm format.
I don't think I've ever run across that one.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
25 Apr
25 Apr
11:18 p.m.
New subject: tape drives (IBM SSA, IBM England -> Xyratex)
The cdrom drive may have hooked up directly by SCSI to the host. The
tape drives may have been on the SSA bus.
IBM invented SSA to sabotage Fibre channel back in the day, promised to
merge it so it would be media compatable (not protocol) compatable with
FC to stop FC.
As a result, how many out there have either? only recently has SATA
taken root using some advances in the serial transfer chips.
Anyway the tape drives may or may not be that clean an interface if they
have a bridge or such to the SSA even if you find the 68 pin connectors.
Most of the SSA stuff was built by a company I worked for (over 10 years
ago for purposes of the forum) which was based in Portsmith, England and
with a large facility in Havant England. They are still around after
major implosion making FC and SAN storaage, and are called Xyratex.
IBM gave a group of local (to England) senior management the disk
operation there, and $100m (or # dont recall which) and a 5 years of IBM
support for their hardware there and told them to split it off. As a
result they had a big building wired with Token Ring and OS2 print
servers trying to work with NT. It was wonderful to see such a waste of
time trying to make such junk work.
Anyway, were the SSA systems you had large Power systems, or AS/400?
Also the same IBM division which became Xyratex made some of the 20 and
larger 5 1/4" drives for the AT before before being split off.
Jim
Roy J. Tellason wrote:
On Thursday 24 April 2008 17:34, Chuck Guzis wrote:
>> Date: Thu, 24 Apr 200
<snip>
These were a part of an IBM box, SSA? Something like
that. LOTS of hard
drives in there, and some sort of a serial link (loop?) to the computer(s).
>> I'm told that these hold 20G on a tape. The guy I go
<snip>
26 Apr
26 Apr
6:33 a.m.
New subject: tape drives (IBM SSA, IBM England -> Xyratex)
On Saturday 26 April 2008 02:18, jim s wrote:
The cdrom drive may have hooked up directly by SCSI to
the host. The
tape drives may have been on the SSA bus.
IBM invented SSA to sabotage Fibre channel back in the day, promised to
merge it so it would be media compatable (not protocol) compatable with
FC to stop FC.
As a result, how many out there have either? only recently has SATA
taken root using some advances in the serial transfer chips.
Anyway the tape drives may or may not be that clean an interface if they
have a bridge or such to the SSA even if you find the 68 pin connectors.
Most of the SSA stuff was built by a company I worked for (over 10 years
ago for purposes of the forum) which was based in Portsmith, England and
with a large facility in Havant England. They are still around after
major implosion making FC and SAN storaage, and are called Xyratex.
IBM gave a group of local (to England) senior management the disk
operation there, and $100m (or # dont recall which) and a 5 years of IBM
support for their hardware there and told them to split it off. As a
result they had a big building wired with Token Ring and OS2 print
servers trying to work with NT. It was wonderful to see such a waste of
time trying to make such junk work.
Anyway, were the SSA systems you had large Power systems, or AS/400?
The system I got bits out of was a rather large rack, though the guy who was
storing it at his place was able to transport it in his van. What I've
gotten out of there so far is a whole bunch of those plug-in drives, mostly
around 4.3 or 4.5GB, two different types -- one type has oddball connections
on the back of the drive itself making them otherwise useless to me, the
other has a 68-pin connection, which plugs into a little board that fits in
to the plastic enclosure that holds the drive. There's also one enclosure
that you can plug a whole mess of these into, currently down in the
basement. I would tend to assume that some power supplies (probably more
than one) would get plugged into that. I have two different types of power
supply that came with this stuff as well, listed toward the bottom of this
page:
http://mysite.verizon.net/rtellason/pwrsup.html
And one that I haven't dug into yet is still sitting in a box, I think it's
another enclosure of this sort, but it's not nearby and I haven't had the
chance to go and get it yet. That box was still sealed with "IBM tape" until
I popped it to get the manual out that was on top of things.
These enclosures apparently went into the big rack that the guy still has, or
had the last time I was out there, I haven't been in touch with him for a
while now.
They apparently had two complete systems at one point in time, the one I'm
getting having been a backup.
Nobody that I've talked to has expressed any interest whatsoever in any of
this stuff, the usual comment being that the drives were "too small". So
I'll be salvaging what I can out of the stuff, and scrapping the rest of it.
Maybe build a RAID5 array or two out of some of those 68-pin drives if I can
find the right cabling and a box big enough to put a bunch of drives into.
I'm told that the whole setup was "replaced by PCs". I've no idea what
they're running on them, though...
<snip>
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
8:53 a.m.
New subject: tape drives (IBM SSA, IBM England -> Xyratex)
On Apr 26, 2008, at 2:18 AM, jim s wrote:
The cdrom drive may have hooked up directly by SCSI to
the host.
The tape drives may have been on the SSA bus.
IBM invented SSA to sabotage Fibre channel back in the day,
promised to merge it so it would be media compatable (not protocol)
compatable with FC to stop FC.
As a result, how many out there have either?
Umm, what? Unless you're in the twilight zone, FC is everywhere.
I've not seen a datacenter *without* tons of FC for many years, and
it won't be going away anytime soon. It'll get upgraded in phases as
it gets faster (4Gbps FC is en vogue now, for companies with lots of
money) but it'll be here for quite a while.
SAN-based RAID systems are, by far, the dominant large-capacity
storage mechanism in use today...and FC is, by far, the dominant
interconnect for those SANs. iSCSI has shown up here and there, but
is not typically used for large installations...it's handy to build a
SAN on an already-installed high-speed Ethernet network without
adding an entirely separate network infrastructure for FC.
-Dave
--
Dave McGuire
Port Charlotte, FL
9:52 a.m.
New subject: tape drives (IBM SSA, IBM England -> Xyratex)
FC is everywhere at the high end.
It was intended to be marketed as something that would displace the
parallel interfaces on the market such as SCSI and ATA.
ATA has won the low end despite its inherent problems and the large
capacity to price war.
SAS is what I see a lot of.
Jim
Dave McGuire wrote:
On Apr 26, 2008, at 2:18 AM, jim s wrote:
--
**********************************
*
* note my email address is changing to jws at jwsss.com
*
**********************************
The cdrom drive may have hooked up directly by
SCSI to the host. The
tape drives may have been on the SSA bus.
IBM invented SSA to sabotage Fibre channel back in the day, promised
to merge it so it would be media compatable (not protocol) compatable
with FC to stop FC.
As a result, how many out there have either?
Umm, what? Unless you're in the twilight zone, FC is everywhere.
I've not seen a datacenter *without* tons of FC for many years, and it
won't be going away anytime soon. It'll get upgraded in phases as it
gets faster (4Gbps FC is en vogue now, for companies with lots of
money) but it'll be here for quite a while.
SAN-based RAID systems are, by far, the dominant large-capacity
storage mechanism in use today...and FC is, by far, the dominant
interconnect for those SANs. iSCSI has shown up here and there, but
is not typically used for large installations...it's handy to build a
SAN on an already-installed high-speed Ethernet network without adding
an entirely separate network infrastructure for FC.
-Dave
3:29 p.m.
New subject: tape drives (IBM SSA, IBM England -> Xyratex)
jim s wrote:
FC is everywhere at the high end.
It was intended to be marketed as something that would displace the
parallel interfaces on the market such as SCSI and ATA.
...which it effectively did, at least for the former. It's a shame
about the latter. :-( While SATA is quite nice (in my opinion), despite
its name it really bears little resemblance to ATA, and in the face of
FC, I see little reason for it to exist. It is a welcome replacement
for the unbelievably kludgy ATA, though, so I don't complain about it
much. :)
ATA has won the low end despite its inherent problems
and the large
capacity to price war.
Unfortunately. :-(
SAS is what I see a lot of.
On non-SAN-based mid- to higher-end systems, yes, my experience is
the same.
-Dave
--
Dave McGuire
Cape Coral, FL
30 Apr
30 Apr
1:53 p.m.
New subject: tape drives (IBM SSA, IBM England -> Xyratex)
Umm, what? Unless you're in the twilight zone, FC
is everywhere.
I've not seen a datacenter *without* tons of FC for many years,
I work for an ISP. Our machine room is not huge, but not tiny either
(it's pulling some 20 kW), and we've got little enough FC that I've
never noticed any. (We have almost no fiber at all; what little we
have, as far as I can recall, is limited to pipes to/from the outside
world.)
We don't go in for the "big honkin' server with lots of little pod
machines" design in general, which might be relevant. Also possibly
relevant is that a large fraction - probably well over half - of our
machine room is customer co-lo gear, mostly with only a few machines
per customer.
/~\ The ASCII der Mouse
\ / Ribbon Campaign
X Against HTML mouse at rodents.montreal.qc.ca
/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
3:19 p.m.
New subject: tape drives (IBM SSA, IBM England -> Xyratex)
On Wednesday 30 April 2008, der Mouse wrote:
Heh.
Our main machine room(s) (two, with doors interconnecting them) draw
about 1.1MW of power, which doesn't account for the power used to chill
the water to the CRAC units.
We just set up cluster in a small machine room that only holds about 12
racks, and is using up about 60kW. :)
We do have some FC on our big storage devices (a tape library that has a
few thousand slots, and our couple of BlueArc Titan NAS boxes), but
that's about it.
If you're not really careful with FC, or using a very small, completely
homogenous (including firmware version) setup, it's really easy to have
big problems that affect everything on the SAN. The administrative
group on campus recently had some problems with their EMC-based SAN,
which resulted in various machines overwriting filesystems/LUNs
belonging to other machines. From what I heard, the root cause was the
fact that they had different firmware versions on some of their EMC FC
switches. (Or, perhaps, because they're using EMC gear...)
Pat
--
The Computer Refuge --- http://computer-refuge.org
Umm, what?
Unless you're in the twilight zone, FC is everywhere.
I've not seen a datacenter *without* tons of FC for many years,
I work for an ISP. Our machine room is not huge, but not tiny either
(it's pulling some 20 kW)
1 May
1 May
5:16 a.m.
New subject: tape drives (IBM SSA, IBM England -> Xyratex)
On Apr 30, 2008, at 6:19 PM, Patrick Finnegan wrote:
--
Dave McGuire
Port Charlotte, FL
If you're not really careful with FC, or using a
very small,
completely
homogenous (including firmware version) setup, it's really easy to
have
big problems that affect everything on the SAN. The administrative
group on campus recently had some problems with their EMC-based SAN,
which resulted in various machines overwriting filesystems/LUNs
belonging to other machines. From what I heard, the root cause was
the
fact that they had different firmware versions on some of their EMC FC
switches. (Or, perhaps, because they're using EMC gear...)
...which is precisely why I avoid EMC gear. They are the
Microsoft of the high-end storage world. Complete and utter crap
products, tremendously overpriced, but a damn good marketing
department. Every EMC installation I've seen has had those types of
difficulties. Like Microsoft, I have no idea why people keep buying
this garbage.
-Dave
5:14 a.m.
New subject: tape drives (IBM SSA, IBM England -> Xyratex)
On Apr 30, 2008, at 4:53 PM, der Mouse wrote:
I used to (and sorta still do) work for an ISP as well...a smaller
one than yours from the sound of things, but I've worked for several
over the years, large and small. It's not very common in that
environment because it's just not needed in that environment. I
suppose I should've qualified "datacenter" to mean "non-ISP
datacenter" in my earlier message. ;)
-Dave
--
Dave McGuire
Port Charlotte, FL
Umm, what?
Unless you're in the twilight zone, FC is everywhere.
I've not seen a datacenter *without* tons of FC for many years,
I work for an ISP. Our machine room is not huge, but not tiny either
(it's pulling some 20 kW), and we've got little enough FC that I've
never noticed any. (We have almost no fiber at all; what little we
have, as far as I can recall, is limited to pipes to/from the outside
world.)
We don't go in for the "big honkin' server with lots of little pod
machines" design in general, which might be relevant. Also possibly
relevant is that a large fraction - probably well over half - of our
machine room is customer co-lo gear, mostly with only a few machines
per customer.
5847
days inactive
5854
days old
10 comments
6 participants
participants (6)
-
cclist＠sydex.com -
jws＠jwsss.com -
mcguire＠neurotica.com -
mouse＠Rodents.Montreal.QC.CA -
pat＠computer-refuge.org -
rtellason＠verizon.net