On Aug 1, 2006, at 22:23, Luke Lonergan wrote:
Torrey,
On 8/1/06 10:30 AM, "Torrey McMahon" <[EMAIL PROTECTED]> wrote:
http://www.sun.com/storagetek/disk_systems/workgroup/3510/index.xml
Look at the specs page.
I did.
This is 8 trays, each with 14 disks and two active Fibre channel
attachments.
That means that 14 disks, each with a platter rate of 80MB/s will
be driven
over a 400MB/s pair of Fibre Channel connections, a slowdown of
almost 3 to
1.
This is probably the most expensive, least efficient way to get disk
bandwidth available to customers.
WRT the discussion about "blow the doors", etc., how about we see some
bonnie++ numbers to back it up.
actually .. there's SPC-2 vdbench numbers out at:
http://www.storageperformance.org/results
see the full disclosure report here:
http://www.storageperformance.org/results/b00005_Sun_SPC2_full-
disclosure_r1.pdf
of course that's a 36GB 15K FC system with 2 expansion trays, 4HBAs
and 3 yrs maintenance in the quote that was spec'd at $72K list (or
$56/GB) .. (i'll use list numbers for comparison since they're the
easiest )
if you've got a copy of the vdbench tool you might want to try the
profiles in the appendix on a thumper - I believe the bonnie/bonnie++
numbers tend to skew more on single threaded low blocksize memory
transfer issues.
now to bring the thread full circle to the original question of price/
performance and increasing the scope to include the X4500 .. for
single attached low cost systems, thumper is *very* compelling
particularly when you factor in the density .. for example using list
prices from http://store.sun.com/
X4500 (thumper) w/ 48 x 250GB SATA drives = $32995 = $2.68/GB
X4500 (thumper) w/ 48 x 500GB SATA drives = $69995 = $2.84/GB
SE3511 (dual controller) w/ 12 x 500GB SATA drives = $36995 = $6.17/GB
SE3510 (dual controller) w/ 12 x 300GB FC drives = $48995 = $13.61/GB
So a 250GB SATA drive configured thumper (server attached with 16GB
of cache .. err .. RAM) is 5x less in cost/GB than a 300GB FC drive
configured 3510 (dual controllers w/ 2 x 1GB typically mirrored
cache) and a 500GB SATA drive configured thumper (server attached) is
2.3x less in cost/GB than a 500GB SATA drive configured 3511 (again
dual controllers w/ 2 x 1GB typically mirrored cache)
For a single attached system - you're right - 400MB/s is your
effective throttle (controller speeds actually) on the 3510 and your
realistic throughput on the 3511 is probably going to be less than
1/2 that number if we factor in the back pressure we'll get on the
cache against the back loop .. your bonnie ++ block transfer numbers
on a 36 drive thumper were showing about 424MB/s on 100% write and
about 1435MB/s on 100% read .. it'd be good to see the vdbench
numbers as well (but i've have a hard time getting my hands on one
since most appear to be out at customer sites)
Now with thumper - you are SPoF'd on the motherboard and operating
system - so you're not really getting the availability aspect from
dual controllers .. but given the value - you could easily buy 2 and
still come out ahead .. you'd have to work out some sort of timely
replication of transactions between the 2 units and deal with failure
cases with something like a cluster framework. Then for multi-
initiator cross system access - we're back to either some sort of NFS
or CIFS layer or we could always explore target mode drivers and
virtualization .. so once again - there could be a compelling
argument coming in that arena as well. Now, if you already have a
big shared FC infrastructure - throwing dense servers in the middle
of it all may not make the most sense yet - but on the flip side, we
could be seeing a shrinking market for single attach low cost arrays.
Lastly (for this discussion anyhow) there's the reliability and
quality issues with SATA vs FC drives (bearings, platter materials,
tolerances, head skew, etc) .. couple that with the fact that dense
systems aren't so great when they fail .. so I guess we're right back
to choosing the right systems for the right purposes (ZFS does some
great things around failure detection and workaround) .. but i think
we've beat that point to death ..
---
.je
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