Veritas-bu

[Veritas-bu] ADDL SUMMARY: SAN Tape Drive / Storage / Host Co nnectivity

2003-04-28 19:18:38
Subject: [Veritas-bu] ADDL SUMMARY: SAN Tape Drive / Storage / Host Co nnectivity
From: Mark.Donaldson AT experianems DOT com (Donaldson, Mark)
Date: Mon, 28 Apr 2003 17:18:38 -0600
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I'd have to protest the paragraph below.  Every solaris box, except the most
recent ones (and sometimes even then) have been sold with disks & tapes
sharing busses.  It's not uncommon to have small tape drives & boot drives
sharing the same internal bus.
 
Here's a recently purchased E6800
/dev/sg/c3t6l0: (/dev/rmt/0): "HP      C5683A"
<snip>
/dev/sg/c3t0l0: (/dev/rdsk/c3t0d0): "FUJITSU MAN3184M SUN18G"
 
...showing a disk drive & the "internal" tape drive on single bus.  It's
been like this for years, with CDs, tapes, & various types of disks sharing
SCSI busses.
 
I smell cop-out here from IBM.
 
$.02 - M


-----Original Message-----
From: Chris Madden [mailto:maddenca AT myrealbox DOT com]
Sent: Monday, April 28, 2003 4:04 PM
To: Veritas Users NetBackup (E-mail)
Subject: [Veritas-bu] ADDL SUMMARY: SAN Tape Drive / Storage / Host
Connectivity


 <snippage> 
 
Furthermore, older SCSI drivers were written using a single SCSI profile for
the whole adapter. This was fine since disk and tape were rarely, if ever,
mixed, so a single profile (one for disk or one for tape) could be used for
the whole adapter and work fine. Often this is not under the user's control
- the driver picks a profile based on what devices it sees. HBA drivers
could certainly be written to allow different profiles to be used for
different devices at the same time on a single adapter, but this is not yet
a common practice. Thus, if you do mix disk and tape on a single HBA, you
end up either using a disk profile for both disk and tape, or a tape for
both disk and tape. Some devices will be using a non-optimal profile.
 
 <snippage> 
 
Cheers,
-Chris




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<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=098000923-28042003>I'd 
have to protest the paragraph below.&nbsp; Every solaris box, except the most 
recent ones (and sometimes even then) have been sold with disks &amp; tapes 
sharing busses.&nbsp; It's not uncommon to have small tape drives &amp; boot 
drives sharing the same internal bus.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=098000923-28042003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=098000923-28042003>Here's 
a recently purchased E6800</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=098000923-28042003>/dev/sg/c3t6l0: (/dev/rmt/0): 
"HP&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; C5683A"<BR>&lt;snip&gt;<BR>/dev/sg/c3t0l0: 
(/dev/rdsk/c3t0d0): "FUJITSU MAN3184M SUN18G"</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=098000923-28042003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=098000923-28042003>...showing a disk drive &amp; the "internal" tape 
drive 
on single bus.&nbsp; It's been like this for years, with CDs, tapes, &amp; 
various types of disks sharing SCSI busses.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=098000923-28042003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=098000923-28042003>I 
smell cop-out here from IBM.</SPAN></FONT></DIV>
<DIV><SPAN class=098000923-28042003>&nbsp;</DIV>
<DIV><SPAN class=098000923-28042003></SPAN><FONT face=Arial color=#0000ff 
size=2>$<SPAN class=098000923-28042003>.02 - M</SPAN><BR></FONT></DIV></SPAN>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
  <DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma 
  size=2>-----Original Message-----<BR><B>From:</B> Chris Madden 
  [mailto:maddenca AT myrealbox DOT com]<BR><B>Sent:</B> Monday, April 28, 2003 
4:04 
  PM<BR><B>To:</B> Veritas Users NetBackup (E-mail)<BR><B>Subject:</B> 
  [Veritas-bu] ADDL SUMMARY: SAN Tape Drive / Storage / Host 
  Connectivity<BR><BR></FONT></DIV>
  <DIV>
  <DIV><SPAN class=098000923-28042003><FONT face=Arial color=#0000ff 
  size=2>&nbsp;&lt;snippage&gt;&nbsp;</FONT></SPAN></DIV>
  <DIV><FONT face=Arial size=2></FONT>&nbsp;</DIV>
  <DIV><FONT face=Arial size=2>Furthermore, older SCSI drivers were written 
  using a single SCSI profile for the whole adapter. This was fine since disk 
  and tape were rarely, if ever, mixed, so a single profile (one for disk or 
one 
  for tape) could be used for the whole adapter and work fine. Often this is 
not 
  under the user's control - the driver picks a profile based on what devices 
it 
  sees. HBA drivers could certainly be written to allow different profiles to 
be 
  used for different devices at the same time on a single adapter, but this is 
  not yet a common practice. Thus, if you do mix disk and tape on a single HBA, 
  you end up either using a disk profile for both disk and tape, or a tape for 
  both disk and tape. Some devices will be using a non-optimal 
  profile.</FONT></DIV>
  <DIV><FONT face=Arial size=2></FONT>&nbsp;</DIV>
  <DIV><FONT face=Arial color=#0000ff size=2><SPAN 
  class=098000923-28042003>&nbsp;&lt;snippage&gt;&nbsp;</SPAN></FONT></DIV>
  <DIV><FONT face=Arial size=2></FONT>&nbsp;</DIV>
  <DIV><FONT face=Arial size=2>Cheers,</FONT></DIV>
  <DIV><FONT face=Arial 
size=2>-Chris<BR><BR></FONT></DIV></DIV></BLOCKQUOTE></BODY></HTML>

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