[DRBD-user] Dell Server Question

Roof, Morey R. MRoof at admin.nmt.edu
Fri Dec 9 20:53:37 CET 2011

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Hi Michael,

Thanks a bunch for the information.  I was looking at the Supermicro
boxes (used quite a few of them) and was a bit curious about the Dell
offering.  I'm glad to know I shouldn't use them and I believe I will
just go with the Supermicro setup as I was planning.

One big issue I wanted to know was the backplane for the HDDs.  Having
it split like that it is really stupid.  With the supermicro chassis
they can be ordered with dual expander chips so cards like the Megaraid
can load balance the IO to both ports on the HDDs.

Pretty sad that Dell would act like that but it is their loss.

Thanks again,
Morey

-----Original Message-----
From: Kushnir, Michael (NIH/NLM/LHC) [C]
[mailto:michael.kushnir at nih.gov] 
Sent: Friday, December 09, 2011 11:53 AM
To: Roof, Morey R.; drbd-user at lists.linbit.com
Subject: RE: Dell Server Question

Hi Morey,

I am using two C2100 servers with 2.5" inch chassis with DRBD. To save
you the long read, my quick and short recommendation is: AVOID THEM LIKE
THE PLAGUE! 

For the money, get
http://www.supermicro.com/products/chassis/4U/417/SC417E16-R1400U.cfm
(72-bay - 4U) or the
http://www.supermicro.com/products/chassis/2U/216/SC216E16-R1200U.cfm
(24 bay - 2U) instead.

If you want more detailed info, read on! :)

 My servers came with the LSI 9260-8i RAID cards, single E5620 CPU, 12GB
RAM, and the Intel based "mezzanine" dual-port 10GbE card. The backplane
is split with 12 slots connected to one port on the RAID card, and 12
slots on the other. 

CPU and RAM:
I've found the E5620 is more than capable of handling the load from DRBD
and IET (software iscsi target). 12GB RAM is also ample for my needs.

Network:
I've found the Intel 10GbE card to be a good performer. I am using it
with Finisar SFP+ modules and have it connected to a Cisco 4900 switch
with Cisco optics on the switch end. I have the two ports in an LACP
(mode 4) bond.  I am getting ping latencies of about 0.23-0.3ms. I'm
happy with that performance. 

RAID:
I have my OS (RHEL 5) and swap on a pair of 500GB SATA2 disks in RAID1,
and my DRBD on a RAID10 made up of 10 Constellation.2 1TB disks.
Metadata is set to internal. The max replication rate (for the initial
sync)  was ~3.2Gbits/s (measured by iftop).


Issues:

1.

This server is not actually made by Dell. It is completely outsourced to
another manufacturer. I was not able to get any useful support from Dell
with any issues that I had. Their support people simply don't know crap
about this server, how to use it, or how to manage it. Considering that
I'm with the Federal government, and go through a dedicated support
team, that should say something. Dell was not even able to tell me what
software to use to manage the RAID array and failure notifications. 

Dell kept telling me that the LSI command line utility is the only way
to go, and that the server, "is intended for hyper scale environments
where the expectation is that a failed server would just fail and be
replaced by another, and where administrators should know how to manage
such an environment." 

 Thankfully, LSI support people pointed me to their GUI which unlocks
great features like SNMP and SMTP notifications, SSD caching, and SSD
protector for SSD RAID.

2.

Because the hardware is not actually "made" by Dell, this server is not
compatible with Open Manage and you can't update your drivers firmware
from Dell's yum repositories firmware. 

3. 

Drive trays--- wow was this a surprise for me!!! Dell has a new policy
where they do not sell drive trays without hard drives in them. As you
might know, Dell's drives are highly overpriced. They will also not sell
you a server fully populated with trays unless you get it fully
populated with drives. We bought over $100k of Dell equipment this year,
and they would not make an exception and give us the drive trays. 

So, finally, we relented, and we bought 16 (8 for each server) Crucial
M4 512GB SSDs from Dell for about $13k. Once we bought the drives, we
asked for trays. Dell told us to go... The policy is that trays are only
supplied with Dell BRAND drives, not any drives purchased from Dell.

We relented again, and asked Dell to sell us their cheapest hard drives
just to get trays. Dell told us that they cannot, because they are out
of hard drives due to flooding in Thailand. And they cannot just charge
us for drives and ship only the trays. GRR!!! Bastards!!!

 I've tried finding the trays online. It took me months to find some at
codemicro.com. Then they suddenly sold out of all 400+ units. So, the
last batch, I had to buy on eBay. I thank God that Ivan from New Jersey
was able to find some to put them on eBay. 


So, my recommendation is: STAY AWAY! Get the SuperMicro chassis (it
comes with all 72 drive trays and plenty of expansion capacity. Get ASUS
server motherboards (I use them in my private lab), Myri 10GbE  NICs (I
use them in other production servers), and LSI 9260-8i (or better) RAID
cards. You will be in a good place in terms of hardware and money spent.



Best, 
Michael Kushnir

Lead VMware and UNIX Systems Administrator
Communications Engineering Branch,
Lister Hill National Center for Biomedical Communications,
National Library of Medicine,
National Institutes of Health

-----Original Message-----
From: Roof, Morey R. [mailto:MRoof at admin.nmt.edu] 
Sent: Thursday, December 08, 2011 1:30 PM
To: drbd-user at lists.linbit.com
Subject: [DRBD-user] Dell Server Question

Hi Everyone,

Anyone out there using a Dell Poweredge C2100 with the 24 2.5" HDD
backplane?  I'm curious to know a little about the backplane, mainly if
it is a dual port backplane where the RAID controller can use both ports
on the SAS drives to load balance the IO operations.  Dell's website
isn't very specific on this point.  Also, some information about how the
server seems work with DRBD would be very helpful to me.

Thanks,
Morey
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