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VMware ESXi host seeing low iops from E-Series array

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Category:
e-series-systems
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esg
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Applies to

  • E-series
  • VMware ESXi

Issue

Error from VMware ESXi:

"I/O latency increased from average value of 16649 microseconds to 366839 microseconds".

Troubleshooting Steps

  • Verify the number of drives used to create the Volume Group or Disk Pool.
  • Calculate the IOP's based on the disk RPM.
    • Example: If the disk RPM is 7200, per drive can support up to 75-100 iops. 
    • Formula: number of drive in the volume group or disk pool * iops

Note: While calucuating the total iops for disk pool need to exclude the preservation drives count.

Table of the IOPS based on the disk rpm

Device      Type  IOPS             Interface
=========== ===== ================ ===========
7,200 rpm   SATA  ~75-100 IOPS[2]  SATA 3 Gb/s
10,000 rpm  SATA  ~125-150 IOPS[2] SATA 3 Gb/s
10,000 rpm  SAS   ~140 IOPS[2]     SAS
15,000 rpm  SAS   ~175-210 IOPS[2] SAS

  • Verify if there any errors been reported in ISCSI-STATISTICS.CSV file.

clipboard_e22ba97ba08a62edb858f94530a0ef308.png

  • Check if there are any open and queued request on drive side.

-> chall 0
 
chAll (Tick 1261153685) ==> 03/07/24-22:59:11
 
2806-A 08.74.01.00
.....Channels.....:...........Target...........:............Initiator..........:                           
             Link :ITN :..........IOs..........:ITN :............IOs...........:.........Busy.........Idle.
  Ch H/D STP Down :cnt : Open  Completed  Errs :cnt : Qd  Open  Completed  Errs:           Ms           Ms 
---- --- --- ---- :--- :----- ---------- ----- :--- :--- ----- ---------- -----: ------------ -------------
   0 Drv SAS    0 :  1 :    0      42039     0 : 10 :  0    33   63446794     0:     51609897      3232649
   1 Drv SAS    0 :  1 :    0      41952     0 : 10 : 21    45   54312522     0:     51465021      3377524
   2 Hst iSC    0 :  1 :    0   22222954   673 :  0 :  0     0          0     0:     54842546            0
   3 Hst iSC    0 :  1 :   36   22218796   462 :  0 :  0     0          0     0:     54842546            0
   4 Drv iSA    0 :  0 :    0          0     0 :  1 :  0     0        315     0:          489     54842056

  • Verify if there are any packet drops/errors from the network level.

 

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