[Veritas-bu] PCI bus and HBA throughput
2003-04-25 10:42:50
Subject: |
[Veritas-bu] PCI bus and HBA throughput |
From: |
Eric.Shafto AT drkw DOT com (Shafto, Eric) |
Date: |
Fri, 25 Apr 2003 10:42:50 -0400 |
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It would be interesting to see whether the situation improves noticeably
with multiple HBAs. Does anyone have some data to share?
-----Original Message-----
From: Paul Winkeler [mailto:pwinkeler AT pbnj-solutions DOT com]
Sent: Friday, April 25, 2003 8:57 AM
To: 'Vijay Korde'
Cc: veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] PCI bus and HBA throughput
Hi Vijay
Here is what we found using two other brands of PCI Bus 2Gbit HBA's in
SunFire 880's going to T9904B's:
1) To a single drive using 2Gbit HBA's, observed peak ~40MByte/sec,
regardless of 33 or 66Mhz bus
2) Writing 3 streams to 3 drives across the same 2Gbit HBA, observed peak
~100MByte/sec regardless of 33 or 66Mhz bus
During all tests source data was fully cached in RAM (machine had 8GByte)
and no other processes running (machine had 8 CPU's)
Wconcluded that the bottleneck was likely in the handling of the SAN
protocols across the HBA. Our basis for this conclusion was this:
- Writing zeroes (/dev/zero) to a single T9940B drive yielded a rate of
69MByte/sec which is basically the upper limit at which StorageTek claims
the drive can take data in; so we know it can go that fast.
- Pushing zeroes to 2 drives simultaneously can be done at an aggregate rate
of ~130MByte/sec on the 66MHz bus, closer to ~120MByte/sec on the 33Mhz bus.
- Going to 3 simultaneous drives with zeroes yields rates of ~138MByte/sec
and 129MByte/sec respectivel for the 66MHz and 33Mhz buses.
In other words, the bus speed gave the 66Mhz bus a slight edge but hardly
worth bothering. It would be very interesting to see what the results look
like when you use multiple HBA's simultaneously...
My advice: don't hang more than 2 drives of a single HBA.
PaulW
www.pbnj-solutions.com <http://www.pbnj-solutions.com/> IT Solutions That
Stick
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<DIV><SPAN class=091074214-25042003><FONT face=Arial color=#0000ff size=2>It
would be interesting to see whether the situation improves noticeably with
multiple HBAs. Does anyone have some data to share?</FONT></SPAN></DIV>
<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> Paul Winkeler
[mailto:pwinkeler AT pbnj-solutions DOT com]<BR><B>Sent:</B> Friday, April
25, 2003
8:57 AM<BR><B>To:</B> 'Vijay Korde'<BR><B>Cc:</B>
veritas-bu AT mailman.eng.auburn DOT edu<BR><B>Subject:</B> RE: [Veritas-bu]
PCI bus
and HBA throughput<BR><BR></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=426311712-25042003>Hi
Vijay</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=426311712-25042003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=426311712-25042003>Here
is what we found using two other brands of PCI Bus 2Gbit HBA's in SunFire
880's going to T9904B's:</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=426311712-25042003>1)
To a single drive using 2Gbit HBA's, observed peak ~40MByte/sec, regardless
of
33 or 66Mhz bus</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=426311712-25042003>2)
Writing 3 streams to 3 drives across the same 2Gbit HBA, observed peak
~100MByte/sec regardless of 33 or 66Mhz bus</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=426311712-25042003>During all tests source data was fully cached in RAM
(machine had 8GByte) and no other processes running (machine had 8
CPU's)</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=426311712-25042003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=426311712-25042003>Wconcluded that the bottleneck was likely in the
handling of the SAN protocols across the HBA. Our basis for this
conclusion was this:</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=426311712-25042003>-
Writing zeroes (/dev/zero) to a single T9940B drive yielded a rate of
69MByte/sec which is basically the upper limit at which StorageTek claims the
drive can take data in; so we know it can go that fast.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=426311712-25042003>-
Pushing zeroes to 2 drives simultaneously can be done at an aggregate
rate of ~130MByte/sec on the 66MHz bus, closer to ~120MByte/sec on the 33Mhz
bus.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=426311712-25042003>-
Going to 3 simultaneous drives with zeroes yields rates of ~138MByte/sec and
129MByte/sec respectivel for the 66MHz and 33Mhz buses.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=426311712-25042003>In
other words, the bus speed gave the 66Mhz bus a slight edge but hardly worth
bothering. It would be very interesting to see what the results look
like when you use multiple HBA's simultaneously...</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=426311712-25042003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=426311712-25042003>My
advice: don't hang more than 2 drives of a single HBA.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=426311712-25042003></SPAN></FONT> </DIV>
<DIV align=left><FONT face=Arial size=2>PaulW</FONT></DIV>
<DIV align=left><FONT face=Arial size=2><A
href="http://www.pbnj-solutions.com/">www.pbnj-solutions.com</A> IT Solutions
That Stick</FONT></DIV></BLOCKQUOTE><FONT SIZE=3><BR>
<BR>
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