DTN - shawfdong/hyades GitHub Wiki

dtn.ucsc.edu is UCSC's Data Transfer Node. It is a Dell PowerEdge R510, equipped with two (2x) quad-core Intel Westmere Xeon E5620 processors at 2.40GHz, and 24GB memory.

Table of Contents

Storage

The RAID controller of dtn is a PERC H700 Integrated[1], as reported by:

# omreport storage controller

but is actually a rebranded LSI MegaRAID SAS 2108:

# lspci | grep RAID
02:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 2108 [Liberator] (rev 05)

Two virtual disks are configured on the RAID controller. One is a RAID-1 volume (/dev/sda), comprised of two 146 GB SAS drives; and the other is a RAID-6 volume (/dev/sdb), comprised of twelve (12x) 1TB SAS drives. The former is used for the OS. On the latter is created an XFS file system, which is mounted at /data.

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda6       117G  1.6G  109G   2% /
tmpfs            12G     0   12G   0% /dev/shm
/dev/sda1       248M  101M  135M  43% /boot
/dev/sda5       3.9G   72M  3.6G   2% /tmp
/dev/sda2       9.7G  485M  8.7G   6% /var
/dev/sdb1       9.1T   11G  9.1T   1% /data

For more information, see dtn Benchmarks.

Network

There are 2 on-board Broadcom GbE interfaces. 10 GbE connections are provided by a dual-port Intel 82599ES 10 Gigabit Ethernet Controller.

$ lspci | grep Ethernet
01:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5716 Gigabit Ethernet (rev 20)
01:00.1 Ethernet controller: Broadcom Corporation NetXtreme II BCM5716 Gigabit Ethernet (rev 20)
03:00.0 Ethernet controller: Intel Corporation 82599ES 10-Gigabit SFI/SFP+ Network Connection (rev 01)
03:00.1 Ethernet controller: Intel Corporation 82599ES 10-Gigabit SFI/SFP+ Network Connection (rev 01)

Officially, Intel doesn't sanction other brands of SFP+ optical modules to work with Intel 10 Gigabit Ethernet adapters[2]. When a non-Intel branded SFP+ optical module, the Linux kernel module ixgbe (driver for Intel GbE adapters) will fail to load and it will post a message into dmesg like the following:

ixgbe 0000:03:00.0: failed to load because an unsupported SFP+ module type was detected.

Fortunately, the Linux kernel module ixgbe permits a workaround:

# modinfo ixgbe | grep parm
parm:           allow_unsupported_sfp:Allow unsupported and untested SFP+ modules on 82599-based adapters (uint)

To manually unload the ixgbe module and then reload the module with the parameter allow_unsupported_sfp, run

# modprobe -r ixgbe
# modprobe ixgbe allow_unsupported_sfp=1

If it works, you can make it permanent (to survive reboots), by running:

# echo "options ixgbe allow_unsupported_sfp=1" > /etc/modprobe.d/ixgbe-options.conf
# depmod -a

Globus

It is only befitting to have Globus Toolkit installed on the Data Transfer Node. The Globus endpoint name for dtn is ucsc#dtn. For more details, see Globus on dtn.

References

  1. ^ DELL PERC H700 and H800 Technical Guide
  2. ^ Intel Ethernet SFP+ Optics
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