Re: [Iscsitarget-devel] Hardware Opinion

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I'm not very familiar with HP's offerings - I had only seen several
threads in the VMWare forums mentioning the P400 unfavorably.  Model
numbers aside some key aspects in good hardware controllers:
- PCI-X or preferable PCIe interface (PCI has no place in this arena
today)
- On-controller RAM 256MB or more
- Support for large volumes > 2TB (if this is an issue for you)
- All the staples: Background integrity scans, adjustable rebuild rates,
drive roaming, etc.
- Good management tools for the host OS

If you're going to be serving up VM's and data from one server, aim to
create 2 different Raid sets, one for VM's, one for data/other - this
keeps your disk contention minimized.  Put your VM's on 15K RPM drives.
Remember the cost savings of VM's versus physical and use some of that
to justify the proper storage investment.  I've ran VM's against a 8
drive R10 SATAII (3ware controller) and hit the wall in the past.

You don't need hardware HBA on IET side - you wouldn't need IET in such
a case!  If your storage box is only running IET you won't have any
computational issues.  A server NIC should work just fine.

I've read opinions on both sides of software vs hardware HBA.  I'm a fan
of software.  The cost of hardware iSCSI HBAs and the limited list of
available solutions leads me to believe they are not widely adopted.  If
you are squeezing so much out of a system that being concerned about
NIC&Software overhead versus hardware HBA, you're likely squeezing your
systems too hard or should be using FC.

Jeff

-----Original Message-----
From: isc...@li...
[mailto:isc...@li...] On Behalf Of
Joseph L. Casale
Sent: Wednesday, August 20, 2008 11:05 AM
To: 'isc...@li...'
Subject: Re: [Iscsitarget-devel] Hardware Opinion

Great info! I could always dump the P400, what is your reco
as far as an HP controller goes? Also, I can always use a
hardware iSCSI HBA on the esx server, but what should I use
on the iet side? Just standard NICs?

Thanks guys!
jlc

-----Original Message-----
From: isc...@li...
[mailto:isc...@li...] On Behalf Of
Ross S. W. Walker
Sent: Wednesday, August 20, 2008 8:18 AM
To: Hengesbach, Jeff; isc...@li...
Subject: Re: [Iscsitarget-devel] Hardware Opinion

I agree with Jeff here, it's not so much the processor these
days, but the disk subsystem.

Look for a recognized reliable RAID controller capable of
supporting all RAID levels, especially RAID10, which is the
RAID level of choice for VMs and Databases, save RAID5 and 6
for file services and streaming media, but with storage
prices continuing to fall why not RAID10 everything!

The problem these days is with platters reaching up to 1TB
the risk of a second disk failure during a rebuild becomes
very real. It can take 24 or more hours to rebuild a 6 disk
array and the increased numbers of disks, plus increased
size... the risks are just too high. I like to stick with
250GB for RAID5/6 disks, 500GB for RAID10 disks and if the
number of disks goes over 5 for a RAID5/6 start thinking
RAID50/60 to reduce the risk.

-Ross

> -----Original Message-----
> From: isc...@li...
> [mailto:isc...@li...] On
> Behalf Of Hengesbach, Jeff
> Sent: Wednesday, August 20, 2008 9:33 AM
> To: isc...@li...
> Subject: Re: [Iscsitarget-devel] Hardware Opinion
>
> JLC,
>
> You won't likely have any CPU related slowdowns. A modern
> CPU in a box with good NIC(s) that is only doing IET can
> handle a fairly substantial workload with the right disk
> subsystem. The biggest bottlenecks will be the network and
> disk subsystem. I haven't read too many stellar reviews of
> the PCI P400 controller in that model - and it does not
> support RAID 10. VM's generate lots of small random IO and
> putting that many VM's against a RAID 5 will generate a lot
> of disk IOs.
>
> I've currently got 10 VM's running against a 6 disk R10
> (15K SAS) in a Dell 1900 IET server linked up to the
> network w 2 bonded NICS.  3 of those VM's are high load
> Citrix servers and I can still see enough IO headroom for
> at least 2-4 more VM's.  CPU use is next to nothing.
>
> IET is great and any modern spec'd system will handle IET's
> workload (not talking about disk or networking) just fine.
> The other part of your question really gets into other
> topics - VM capacity, controller / disk configuration and
> selection.  VMWare has some great forums for those
> questions.
>
> Jeff
>
> -----Original Message-----
> From: isc...@li...
> [mailto:isc...@li...] On
> Behalf Of Joseph L. Casale
> Sent: Tuesday, August 19, 2008 5:28 PM
> To: 'isc...@li...'
> Subject: [Iscsitarget-devel] Hardware Opinion
>
> Hey guys,
> It looks like I am rolling out another iSCSI box for vmware
> and general disc provisioning. I was thinking of using the
> HP DL320s chassis but am concerned about processor capacity
> in the box. Max spec is a single Dual-Core Intel Xeon
> Processor 3070 w/8gb ram.
>
> Would this yield acceptable results with a CentOS 5.2 OS
> carving out space from LVM into iet for a single esx server
> w/ ~10 vm's and possible a few luns into physical windows
> boxes?
>
> Thanks!
> jlc

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