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:[email protected]] 
Sent: Thursday, December 08, 2011 1:30 PM
To: [email protected]
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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