Re: [ADSM-L] Maximum throughput with Windows 2003

Hi

Block size, queue depth, sequential v random read, back end
spindles/design, array cache size, other array traffic etc will all play a
part.

On an Windows system with default NTFS block size, with queue depth of 16,
on a dedicated HDS array I can quite easily sustain approx 400MBs on a
sequential read, load balanced over two paths. Obviously Pre fetch is
coming into play to sustain this type of throughput on a sequential read.
Its different hardware but it does show the capability of the OS.

I actually believe Exchange uses a 4K block size, and therefore despite
having larger IOPS, you will see quite a hit on throughput. The ability of
your array front end processors will start to play a part. Also, 10K disks
probably aren't the best. RAID 5 can be better suited to some IO profiles
for Exchange and maybe worth while checkin log v db disk requirements.
Based on this, the read of the data may be more of an issue than the write
out to VTL.

Will the VTL be doing any in-line de-dup etc? which may affect the ability
to write into the VTL?

Ian Smith




Andy Huebner <Andy.Huebner AT ALCONLABS DOT COM>
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11/09/2007 17:53
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Re: [ADSM-L] Maximum throughput with Windows 2003






I do not believe the OS will be a limiting factor.  In the past x86
hardware was an issue due to limited PCI busses, but with PCI Express
that problem should be resolved for the card count you have.  I suspect
your limiting factor will be the number of I/Os per second, if it makes
sense for the app, set you NTFS block size to 64k to match the DMX3.
The highest throughput I have seen from a DMX2000 is around 100 MB/Sec,
which is about half of the 2Gb HBA.
Your throughput will be very dependant on the hyper layout on the disks,
the other traffic on the FA, and how efficient the PCI Express bus
really is.  I would guess you will see 150+MB/sec from a single stream.
I would also say it should be tweakable to go faster.

Do you know what the sustained throughput is for the physical hard
drives?

Andy Huebner
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Kenny
Sent: Tuesday, September 11, 2007 8:58 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Maximum throughput with Windows 2003

Hi Andy,

Thanks for commenting.

I do plan on using PCIe HBA's. I also am evaluating a 4GB VTL. I do not
think the bottleneck will be at the VTL or the disk array (DMX3).

I am trying to determine the single stream performance. If I mount a
single BCV (NTFS) assuming no bottleneck on the disk array or VTL, what
throughput can I expect?

If I mounted 2 BCV NTFS volumes, can I expect a increase in throughput?

I am not sure what the maximum throughput that can be achieved with a
Windows 2003 box versus the maximum throughput that can be obtained with
TSM running on that same hardware?

Thanks,


Pat

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