Skip to content

DellRAID

Jump to bottom
robnagler edited this page Mar 25, 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

See Issue 142 for detailed disussion.

Summary:

  • H310 (non-RAID) controller is 20% faster than an S110 (motherboard).
  • SSD performance varies wildly (2x)
  • Luks and mdadm don't move the needle much

References on performance of hardware RAID vs madam:

Clone this wiki locally