Skip to content

DellRAID

robnagler edited this page Jan 5, 2018 · 15 revisions

Configuring Dell RAID Controller (PERC)

Our RAID disks are really Just a Bunch of Disks (JBOD) as it is easier to manage disks from the file system. ZFS and Linux RAID want to talk to the disks directly, and it's easier to move such disks around.

We've encapsulated all the m620 setup code in idrac-m620-setup.sh, which is a sequence of functions you can selectively execute, including idrac.

RAID And Storage Configuration using RACADM Commands in iDRAC7 is a simple manual documenting the raid commands. RACADM Command Line Reference Guide for iDRAC7 1.50.50 and CMC 4.5 (p106) is the complete reference.

Configure JBOD

We first have to reset the RAID config:

$ idrac 1 storage resetconfig:RAID.Integrated.1-1
$ idrac 1 jobqueue create RAID.Integrated.1-1 -r pwrcycle -s TIME_NOW -e TIME_NA

After this completes, we'll follow ThornLabs instructions:

$ for p in $(idrac 1 raid get pdisks); do
    idrac 1 raid createvd:RAID.Integrated.1-1 -rl r0 -wp wt -rp nra -ss 64k "-pdkey:$p"a
done
$ idrac 1 job RAID.Integrated.1-1

This sets up all the physical disks (pdisks) as independent virtual disks with RAID0 (r0), write through (wt), no read ahead (nra), and 64k strip size (seems what people recommend for SSDs).

Wait a bit and verify that the vdisks have been created:

$ idrac 1 raid get vdisks -o
Disk.Virtual.0:RAID.Integrated.1-1
   Status                           = Ok
   DeviceDescription                = Virtual Disk 0 on Integrated RAID Controller 1
   Name                             = Virtual Disk 0
   RollupStatus                     = Ok
   State                            = Online
   OperationalState                 = Not applicable
   Layout                           = Raid-0
   Size                             = 931.00 GB
   SpanDepth                        = 1
   AvailableProtocols               = SATA
   MediaType                        = SSD
   ReadPolicy                       = No Read Ahead
   WritePolicy                      = Write Through
   StripeSize                       = 64K
   DiskCachePolicy                  = Enabled
   BadBlocksFound                   = NO
   Secured                          = NO
   RemainingRedundancy              = 0
   EnhancedCache                    = Not Applicable
   T10PIStatus                      = Disabled
   BlockSizeInBytes                 = 512

Performance

Issues with H310 controller. Not sure it is a problem for software raid with HDD. Nice answer here: https://serverfault.com/a/685328

http://en.community.dell.com/support-forums/servers/f/906/t/19475037

mdadm vs hardware:

https://delightlylinux.wordpress.com/2016/05/24/motherboard-raid-or-linux-mdadm-which-is-faster/

https://linuxaria.com/pills/how-to-properly-use-dd-on-linux-to-benchmark-the-write-speed-of-your-disk

https://romanrm.net/dd-benchmark

https://linuxaria.com/pills/how-to-properly-use-dd-on-linux-to-benchmark-the-write-speed-of-your-disk

Write through, no read ahead on SSD (Evo 850)

10737418240 B

107 s = 100 MB/s

dd bs=1M count=10240 if=/dev/zero of=test oflag=dsync

45 s = 222 MB/s

dd bs=1M count=10240 if=/dev/zero of=test conv=fdatasync

Clone this wiki locally