Terascala Metadata Target - shawfdong/hyades GitHub Wiki

In the Terascala Lustre Storage, both the Metadata Servers pair connect to a shared Dell MD3220 Storage Array[1]; but only the active Metadata Server mounts the storage array:

There are 2 active/active RAID controllers on the MD3220 Storage Array. Each controller is equipped with four 6Gb SAS ports, and one Ethernet port for LAN out-of-band management. The IP addresses (hostnames) of the 2 Ethernet management ports are 192.168.3.201 (hss3-mdt.A) & 192.168.4.201 (hss3-mdt.B), respectively. We can get a summary report of the Storage Array, using the Dell PowerVault Modular Disk Storage Arrays CLI tool SMcli[2]:

# /opt/dell/mdstoragemanager/client/SMcli hss3-mdt.A hss3-mdt.B -S -quick -c "show storageArray summary;"
Note that here we specify both hostnames of two management ports for redundancy. It is not necessary to specify both; using just one hostname or IP will work too.

There are 24x 2.5" 500GB 7200rpm SAS drives in the Storage Array, as reported by:

# SMcli hss3-mdt.A hss3-mdt.B -S -quick -c "show allPhysicalDisks;"

On those 24 drives is created a RAID-10 volume (virtual disk), as reported by:

# SMcli hss3-mdt.A hss3-mdt.B -S -quick -c "show allVirtualDisks;"

Each controller has a 36-port 6 Gb/s SAS expander that provides access to the drives in the MD3220 enclosure. The SAS expanders enable each controller to access all of the drive ports, creating active/active drives loops that provide both controllers redundant access to all attached disk drives.

MD Storage Manager

The MD3200 series Storage Manager software contains the following packages:

Client
This package contains a GUI tool SMclient and a CLI tool SMcli for monitoring and managing the storage arrays. It also contains an optional monitor service (/etc/init.d/SMmonitor) used to send alerts when there is a critical problem with the storage arrays.
Agent
This package contains software (/etc/init.d/SMagent) that allows a storage management station to communicate with the controllers in the storage array over the I/O path of a host.
Failover Driver
This package contains the multi-path driver (scsi_dh_rdac) used to manage the I/O paths into the controllers in the storage array[3]. If there is a problem on the path or a failure of one of the controllers, the driver automatically re-routes the request from the hosts to the other controller in the storage array.
# modinfo scsi_dh_rdac
filename:       /lib/modules/2.6.32-279.19.1.el6_lustre.2.1.5_1.0.7/kernel/drivers/scsi/device_handler/scsi_dh_rdac.ko
description:    Multipath LSI/Engenio/NetApp E-Series RDAC driver
author:         Mike Christie, Chandra Seetharaman
license:        GPL
vermagic:       2.6.32-279.19.1.el6_lustre.2.1.5_1.0.7 SMP mod_unload modversions 
depends:        
srcversion:     ED7CD76AFDABC40C1912EA1
parm:           rdac_logging:A bit mask of rdac logging levels, Default is 1 - failover logging enabled, set it to 0xF to enable all the logs (int)

References

  1. ^ DELL PowerVault MD3200/MD3220 Series of Storage Arrays
  2. ^ Dell PowerVault Modular Disk Storage Arrays CLI Guide
  3. ^ PowerVault MD3200 Series Storage Arrays - Linux DM Installation Details
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