Benchmark Shenanigans...
Here's a write-up from a former NTAP insider of the
latest EMC press. The configuration for this benchmark
was basically put together to yield good numbers at a
very high price for the configuration.
EMC's SPEC numbers have been out at the SPEC site for
a week now, they either timed the press release to take
away from the Compaq NAS release today, or maybe because
NTAP will be announcing soon.
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See: messages.yahoo.com
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Inside the EMC Celerra Numbers
by: sirbruce70 (30/M/San Jose, CA)
7/31/00 10:35 am
Msg: 26627 of 26643
Okay, let's dissect the latest EMC Celerra NAS results.
Their press release claims it has "at least triple the
performance of the closest competitive NAS (network-
attached storage) offerings" which is of course false.
While it is true that in terms of raw NFS ops it has
greater throughput that other NAS offerings, that's
using a 14 CPU cluster solution. Other NAS vendors
can spread their loads across multiple CPUs, so this
is nothing unique, but most haven't submitted results
for that many CPUs. They submit results for smaller
clusters and the user can use the figures to scale.
But let's go inside the numbers and see how Celerra
compares to the NTAP F760. We'll compare the new
EMC results "to scale" with the NTAP F760 results,
using NFS v3 over TCP:
spec.org
and
spec.org
The F760 delivers 7428 Ops/Sec @ 3.09ms. It does this
by using 2 CPUs, 2 GB of RAM, 64 MB of NVRAM, 42 18GB
disks, and 2 filesystems. That's 3714 Ops/CPU, 3714
Ops/GB of RAM, 116.1 Ops/MB of NVRAM, 176.9 Ops/Disk,
and 3714 Ops/FS. Oh, and that's with RAID-4.
The Celerra 507 Cluster delivers 104067 Ops/Sec @
2.87ms. It does this by using 14 Data Mover CPUs,
but each Symmetrix (there are 6) also had 6 Channel
Directors, and each Channel Director has 2 CPUs.
Channel Directors are not the same as SCSI cards;
those are called Disk Directors. So 6x6x2 + 14 =
86 CPUs total. It also used 7 GB of RAM, 98304 MB
of NVRAM (16 GB in each Symmetrix), 433 (!) disks,
and 14 filesystems. That works out to about 1210
Ops/CPU, 14866 Ops/GB RAM, 1.1 Ops/MB NVRAM, 240.3
Ops/Disk, and 7433.4 Ops/FS.
The EMC results are certainly impressive, as they
deliver more Ops per CPU, RAM, Disk, and FS. But
how do they do it? They use a HUUUUUUUUGE amount
of NVRAM in the Symmetrix. Enourmous, really.
(Actually, it's battery-backed up RAM.) The
affordability of such a configuration is out of
the question. They get less than 1.1 Ops/MB!
Oh, and did I mention the EMC results are
*without* RAID protection, just simple striping.
If you wanted the same performance with RAID
protection, you'd have to buy *twice* as many
disks, which means only 120.1 Ops/Disk and
3716.7 Ops/FS. You could go with RAID-S, but
the performance for RAID-S is far less.
In other words, if you wanted to get 100000+ Ops
with RAID protection, you could buy this one huge
EMC Cluster or several smaller F760 clusters. You
would pay a little more for more CPUs and RAM, but
you'd have to buy MORE disks with the EMC model to
get data protection, and WAY more memory. If we
add the RAM and NVRAM together to be fair (because
NTAP requires more RAM with the above figures and
EMC's NVRAM is really just RAM), you're talking
29568 MB for NTAP and 98311 MB for EMC. That's
3.3 times as much memory - 3.3 times as much money!
There's no comparison... NTAP gives you a lot more
bang for the buck!
Bruce
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