Description:

This article is for system administrators that are using the Round Robin Path Selection Policy (VMW_PSP_RR) on LUNs or volumes mapped from Promise storage arrays to a VMware environment. In addition, the Round Robin Path Selection Policy attemps to balance the I/O load across all active storage paths.

ESXi Round Robin PSP supports two types of limits:

  • IOPS limit: The Round Robin PSP defaults to an IOPS limit with a value of 1000. In this default case, a new path is used after 1000 I/O operations are issued.
  • Bytes limit: The bytes limit is an alternative to the IOPS limit. The bytes limit allows for a specified amount of bytes to be transferred before the path is switched. (Default = 10485760 bytes)
  • Essentially, Round Robin will attempt to rebalance after every 1000 I/Os or 10485760 bytes.

Promise recommends modifying the IOPS limitation to 1 as this may improve performance where an active storage path might have serveral queued I/Os. In addition, setting the limitation to 1 allows other active storage paths to service I/O requests. 

Reference:

https://kb.vmware.com/s/article/2069356


Table of Contents


VTrak Products:


How to change the policy on a Promise LUN to Round Robin PSP (VMW_PSP_RR)

  1. Using the ESXi Shell, invoke the following command syntax to see all the devices:
    esxcli storage nmp device list
  2. Locate the eui (Extended Unique Identifier) of the LUN that you want to change the policy to Round Robin PSP (VMW_PSP_RR)
  3. esxcli storage nmp device list -d eui.2212000155fee67e
    eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Storage Array Type: VMW_SATP_ALUA
    Storage Array Type Device Config: {implicit_support=on; explicit_support=off; explicit_allow=on; alua_followover=on; action_OnRetryErrors=off; {TPG_id=1,TPG_state=ANO}{TPG_id=0,TPG_state=AO}}
    Path Selection Policy: VMW_PSP_MRU
    Path Selection Policy Device Config: Current Path=vmhba64:C0:T0:L0
    Path Selection Policy Device Custom Config:
    Working Paths: vmhba64:C0:T0:L0
  4. Set the path to use Round Robin Path Selection Policy (VMW_PSP_RR):
    esxcli storage nmp device set --device eui.xxxxxx --psp VMW_PSP_RR
  5. For example:
    esxcli storage nmp device set --device eui.2212000155fee67e --psp VMW_PSP_RR
  6. After you invoked the change to VMW_PSP_RR, check the device again to confirm the Path Selection Policy and all the Working Paths:
    esxcli storage nmp device list -d eui.2212000155fee67e
    eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Storage Array Type: VMW_SATP_ALUA
    Storage Array Type Device Config: {implicit_support=on; explicit_support=off; explicit_allow=on; alua_followover=on; action_OnRetryErrors=off; {TPG_id=1,TPG_state=ANO}{TPG_id=0,TPG_state=AO}}
    Path Selection Policy: VMW_PSP_RR
    Path Selection Policy Device Config: {policy=rr,iops=1000,bytes=10485760,useANO=0; lastPathIndex=1: NumIOsPending=0,numBytesPending=0}
    Path Selection Policy Device Custom Config:
    Working Paths: vmhba64:C1:T0:L0, vmhba64:C2:T0:L0, vmhba64:C3:T0:L0, vmhba64:C0:T0:L0
    Is USB: false
  7. You can retrieve a detailed listing of all the paths corresponding to the device mapped to the ESXi server:
    esxcli storage core path list -d eui.2212000155fee67e
    iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d000005,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1-eui.2212000155fee67e
    UID: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d000005,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1-eui.2212000155fee67e
    Runtime Name: vmhba64:C0:T0:L0
    Device: eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Adapter: vmhba64
    Channel: 0
    Target: 0
    LUN: 0
    Plugin: NMP
    State: active
    Transport: iscsi
    Adapter Identifier: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Identifier: 00023d000005,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1
    Adapter Transport Details: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Transport Details: IQN=iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020 Alias= Session=00023d000005 PortalTag=1
    Maximum IO Size: 131072

    iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d00000c,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2-eui.2212000155fee67e
    UID: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d00000c,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2-eui.2212000155fee67e
    Runtime Name: vmhba64:C7:T0:L0
    Device: eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Adapter: vmhba64
    Channel: 7
    Target: 0
    LUN: 0
    Plugin: NMP
    State: active
    Transport: iscsi
    Adapter Identifier: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Identifier: 00023d00000c,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2
    Adapter Transport Details: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Transport Details: IQN=iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020 Alias= Session=00023d00000c PortalTag=2
    Maximum IO Size: 131072

    iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d000008,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2-eui.2212000155fee67e
    UID: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d000008,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2-eui.2212000155fee67e
    Runtime Name: vmhba64:C6:T0:L0
    Device: eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Adapter: vmhba64
    Channel: 6
    Target: 0
    LUN: 0
    Plugin: NMP
    State: active
    Transport: iscsi
    Adapter Identifier: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Identifier: 00023d000008,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2
    Adapter Transport Details: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Transport Details: IQN=iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020 Alias= Session=00023d000008 PortalTag=2
    Maximum IO Size: 131072

    iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d00000b,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2-eui.2212000155fee67e
    UID: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d00000b,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2-eui.2212000155fee67e
    Runtime Name: vmhba64:C5:T0:L0
    Device: eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Adapter: vmhba64
    Channel: 5
    Target: 0
    LUN: 0
    Plugin: NMP
    State: active
    Transport: iscsi
    Adapter Identifier: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Identifier: 00023d00000b,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2
    Adapter Transport Details: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Transport Details: IQN=iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020 Alias= Session=00023d00000b PortalTag=2
    Maximum IO Size: 131072

    iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d000007,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2-eui.2212000155fee67e
    UID: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d000007,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2-eui.2212000155fee67e
    Runtime Name: vmhba64:C4:T0:L0
    Device: eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Adapter: vmhba64
    Channel: 4
    Target: 0
    LUN: 0
    Plugin: NMP
    State: active
    Transport: iscsi
    Adapter Identifier: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Identifier: 00023d000007,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,2
    Adapter Transport Details: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Transport Details: IQN=iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020 Alias= Session=00023d000007 PortalTag=2
    Maximum IO Size: 131072

    iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d00000a,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1-eui.2212000155fee67e
    UID: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d00000a,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1-eui.2212000155fee67e
    Runtime Name: vmhba64:C3:T0:L0
    Device: eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Adapter: vmhba64
    Channel: 3
    Target: 0
    LUN: 0
    Plugin: NMP
    State: active
    Transport: iscsi
    Adapter Identifier: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Identifier: 00023d00000a,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1
    Adapter Transport Details: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Transport Details: IQN=iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020 Alias= Session=00023d00000a PortalTag=1
    Maximum IO Size: 131072

    iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d000006,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1-eui.2212000155fee67e
    UID: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d000006,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1-eui.2212000155fee67e
    Runtime Name: vmhba64:C2:T0:L0
    Device: eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Adapter: vmhba64
    Channel: 2
    Target: 0
    LUN: 0
    Plugin: NMP
    State: active
    Transport: iscsi
    Adapter Identifier: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Identifier: 00023d000006,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1
    Adapter Transport Details: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Transport Details: IQN=iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020 Alias= Session=00023d000006 PortalTag=1
    Maximum IO Size: 131072

    iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d000009,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1-eui.2212000155fee67e
    UID: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01-00023d000009,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1-eui.2212000155fee67e
    Runtime Name: vmhba64:C1:T0:L0
    Device: eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Adapter: vmhba64
    Channel: 1
    Target: 0
    LUN: 0
    Plugin: NMP
    State: active
    Transport: iscsi
    Adapter Identifier: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Identifier: 00023d000009,iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020,t,1
    Adapter Transport Details: iqn.1998-01.com.vmware:5cd9efe4-d033-dace-72ef-341278560000-59c14e01
    Target Transport Details: IQN=iqn.1994-12.com.promise:alias.tgt0000.784b5e5501000020 Alias= Session=00023d000009 PortalTag=1
    Maximum IO Size: 131072

How to adjust the Round Robin IOPS limit from default 1000 to 1

  1. Locate the eui of the device:
    esxcli storage nmp device list -d eui.2212000155fee67e
    eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Storage Array Type: VMW_SATP_ALUA
    Storage Array Type Device Config: {implicit_support=on; explicit_support=off; explicit_allow=on; alua_followover=on; action_OnRetryErrors=off; {TPG_id=1,TPG_state=ANO}{TPG_id=0,TPG_state=AO}}
    Path Selection Policy: VMW_PSP_RR
    Path Selection Policy Device Config: {policy=rr,iops=1000,bytes=10485760,useANO=0; lastPathIndex=1: NumIOsPending=0,numBytesPending=0}
    Path Selection Policy Device Custom Config:
    Working Paths: vmhba64:C1:T0:L0, vmhba64:C2:T0:L0, vmhba64:C3:T0:L0, vmhba64:C0:T0:L0
    Is USB: false
  2. Invoke the following command and replace eui.xxxxxx with the eui of the device :
    for i in `esxcfg-scsidevs -c |awk '{print $1}' | grep eui.xxxxxx`; do esxcli storage nmp psp roundrobin deviceconfig set --type=iops --iops=1 --device=$i; done
  3. For example:
    for i in `esxcfg-scsidevs -c |awk '{print $1}' | grep eui.2212000155fee67e`; do esxcli storage nmp psp roundrobin deviceconfig set --type=iops --iops=1 --device=$i; done
  4. Check the output of the device again:
    esxcli storage nmp device list -d eui.2212000155fee67e
    eui.2212000155fee67e
    Device Display Name: Promise iSCSI Disk (eui.2212000155fee67e)
    Storage Array Type: VMW_SATP_ALUA
    Storage Array Type Device Config: {implicit_support=on; explicit_support=off; explicit_allow=on; alua_followover=on; action_OnRetryErrors=off; {TPG_id=1,TPG_state=ANO}{TPG_id=0,TPG_state=AO}}
    Path Selection Policy: VMW_PSP_RR
    Path Selection Policy Device Config: {policy=iops,iops=1,bytes=10485760,useANO=0; lastPathIndex=2: NumIOsPending=0,numBytesPending=0}
    Path Selection Policy Device Custom Config:
    Working Paths: vmhba64:C1:T0:L0, vmhba64:C2:T0:L0, vmhba64:C3:T0:L0, vmhba64:C0:T0:L0
    Is USB: false

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