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Guide

May 14, 2017

RN3220 / RN4200 Crippling iSCSI Write Performance

I've got a mixed OEM ecosystem with several Tier 2 RN3220's and RN4200's along with Tier 1 EqualLogic storage appliances. All ReadyNAS appliances have 12 drive compliments Seagate Enterprise 4TB ...

iSCSI

slow

Using with a Virtual Hypervisor

Write Performance

ITisTheLaw

Guide

May 23, 2017

I've now swapped into the array an Intel DP NIC and have linked the 10GbE into the system and it's offering even worse performance.

Intel DP ET 1000BASE-T Server Adapter

Switched

9k frames

Tested as one port and dual port RR MPIO

Slightly worse performance in read and write than the built-in adapters

QLogic BCM57810 10GbE 10GSFP+Cu

Point to point on a 3m SFP+DA, no switching involved

No Cluster Shared Volume

On a dedicated 1TB LUN

RAID0 underlying array

Nothing else happening on the array

All other optimisations as above.

Stats 4.png

So I think it's safe to assume it's not any of the NICs involved here.

First few lines of TOP during a benchmark
%Cpu(s): 0.0 us, 1.9 sy, 0.0 ni, 97.7 id, 0.3 wa, 0.0 hi, 0.1 si, 0.0 st
KiB Mem: 3926940 total, 3679804 used, 247136 free, 2196 buffers
KiB Swap: 3139580 total, 0 used, 3139580 free. 3318992 cached Mem

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
6306 root 20 0 0 0 0 S 4.0 0.0 5:23.73 iscsi_trx

Internally, do a lage file copy within a VM and it'll settle at 19.8MB/s

So basically I've inherited several 4x1GbE disk arrays that on 12x 7200 rpm Enterprise SATA drives in RAID 0 cannot write at more than 690Mbps in occasional, yet quite infrequent bursts?

mdgm-ntgr
NETGEAR Employee Retired
May 24, 2017
What's the performance like if you disable Jumbo Frames?

Btw ReadyNAS OS 6.7.3 is now available!
- ITisTheLaw
  Guide
  May 25, 2017
  Hi mdgm,
  
  Thanks for replying,
  
  I have installed 6.7.3 as advised and rebooted.
  
  Going from 9000/1500 on the Netgear, 9014/1514 on the hypervisor yields a more stable sequential file transfer when moving the test VM back in (102GB). It broadly sits between 580 and 660Mbps, predominatly over 600Mbps. This is on 1x1GbE Netgear side. Max Rx on eth2 on the Netgear states 76.7MB (613.6Mbps).
  
  Here is an off thing though, I've set the eth2 IP address to 192.168.171.1 on 1500 MTU and then rebooted the array. Yet, i can still ping 192.168.171.1 with a 8000 byte ICMP echo. ARP confirms that it is talking to the correct NIC.
  
  I've set the hypervisor to 1514
  Jumbo Packet Disabled *JumboPacket {1514}
  
  Rebooted the hypervisor.
  
  Inside the CSV:
  
  Not in a CSV (E:\ as a local iSCSI mount) - this was painful as the array had to copy from and to itself via the Hypervisor. The hypervisor was receiving and sending on the NIC at 380Mbps, the Netgear eth2 says 43.6MB. A larger burst variance was visible during the copy, between 230 and 480Mbps.
  
  Max values on the NICs have dropped to 55.8MB, which would presumably be down to the lack of 9K
  - ITisTheLaw
    Guide
    May 28, 2017
    Incidentally, these are the numbers off of a QNAP TVS-1271U-RP on 12x4TB WD Red over the 10GbE controller, same switch fabric, on a very similar hypervisor (PE R630) near-by on local iSCSI (not CSV).
    
    Spot the difference...