Guidance on specifying Dell PowerEdge servers

General Notes

  • If you are ever likely to want to install a GPU in your server, please consult with the RAT unit to ensure that your proposed specification is suitable for this.
  • Remember that we often re-purpose servers, so whilst specifying internal drives instead of hot-plug drives to save costs might be an acceptable trade-off for the initial purpose, that choice may limit the roles that that server can taken on in the future.
  • Our understanding is that there is no point in using the SmartValue configurations because of the way the University's discount deal applies.
  • The Dell R2x0 range is considered unsuitable for general use as it does not support dual PSUs

Dell Configurator options

Component Note
TPM module Include where offered - we'd probably need to do disk encryption
Chassis configuration Hot Plug drives - allows speedy replacement of dead/dodgy drives (without downtime when combined with RAID)
CPU The default CPU is usually suitable for most purposes
An i3xxx, if available, is often good enough and can be substantially cheaper than the equivalent Xeon
For cpu intensive tasks refer to Passmark for cpu choices.
Clockspeed is not necessarily an indicator of best performance.
For single threaded applications, fewer cores are generally better. Think about what you need, are you buying a racehorse or a pack of huskies
You may need to specify dual processor to make use of all the memory and PCI-e slots
Memory config type Usually "performance optimised" is the best choice as this should fill all the available memory channels.
This Dell whitepaper on 12G servers provides some useful guidance.
Memory DIMM type RDIMMs usually most cost effective, LRDIMMs required for high memory capacity.
Memory Capacity Not expensive, so 8GB should be considered minimum
It is best to leave some expansion space, particularly for eg KVM servers
Fewer, larger, DIMMs can be more cost effective, but too few might affect performance as not all memory channels may be in use
Operating System None
Internal SD module Rarely required (used to boot VMware hypervisor)
RAID configuration Specify a protective level of RAID (typically RAID 1) so that uptime isn't affected by dead disks
RAID 1 + RAID 1 is a common config (first set for O/S, second set for data)
RAID controllers Software RAID (as offered by Dell) is of no use, so you must choose a RAID controller
H730 much more performant than H330
Disks SATA cheaper, larger capacity, but slower (7.2K)
SAS more expensive, smaller capacity, but faster (10K, 15K)
2.5" disks generally consume less energy than 3.5" disks (given same rotational speed)
Don't buy cheap SATA disks that aren't warranted for the full warranty term of the server
SSDs - seek advice from RAT if considering these
You can mix SAS and SATA disks on same controller but not in RAID sets.
Power supplies Dual PSU - gives some protection against power cables being accidentally dislodged and allows for easier re-cabling
Power cords Not required (we buy our own), but if you can't remove from the spec opt for 2m IEC cables
PCI-e riser Choose default configuration unless you have specific requirements for additional PCI-e cards
Embedded Systems Management R2x0 to R5x0 - iDRAC8 Basic
R6x0 to R9x0 - iDRAC8 express
See the Infrastructure report of 24/02/16 for agreed "policy" on choosing an iDRAC.
Network Daughter card Choose default (if present)
Additional network cards There are always network ports in base configuration, so this option isn't required unless the base offering isn't sufficient. Note that third party cards may be cheaper
Bezel Do not specify
Rack Rails ReadyRails sliding without cable management arms - these allow machines to be worked on without being removed from the rack
Warranty Always 5 yrs
Low end (< 1k) - Basic Warranty - NBD
Mid range (1k - 5k) - Basic or ProSupport NBD depending on criticality of server
High end (> 5k) Prosupport NBD
!ProSupport gives us faster access to tech staff and potentially less troubleshooting required by us
Data Protection - keep your hard drive Always specify this option even if you don't expect this server to hold sensitive data - it may be repurposed during its life
Internal Optical drive no
Asset Tag Default

-- AlastairScobie - 29 Feb 2016

Topic revision: r10 - 25 Apr 2016 - 09:56:37 - AlastairScobie
 
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