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FAS2220 CIFS 2 controllers same settings big performance difference

Hi,

we have a FAS2220 with 2 controllers, both have the same setup, same network settings, same cifs settings, plugged in the same switch, switch ports the same settings, connected to the same preferred DC, in general all settings the same but CIFS has a big difference.

Read/Write on a CIFS share from first controller goes 100MBps+, while on the other barely reaches 20-30 and goes up and down.

Strange thing is that there is no performance hit on the second controller for read/write on a VM shared disk over iSCSI.

Here are cifs stat for First controller (good one)

                         reject    0  0%
                           mkdir    0  0%
                           rmdir    0  0%
                            open    0  0%
                          create    0  0%
                           close    0  0%
                         X&close    0  0%
                           flush    0  0%
                         X&flush    0  0%
                          delete    0  0%
                          rename    0  0%
                        NTRename    0  0%
                          getatr    0  0%
                          setatr    0  0%
                            read    0  0%
                          X&read    0  0%
                           write    0  0%
                         X&write    0  0%
                            lock    0  0%
                          unlock    0  0%
                           mknew    0  0%
                          chkpth    0  0%
                            exit    0  0%
                           lseek    0  0%
                        lockread    0  0%
                      X&lockread    0  0%
                     writeunlock    0  0%
                        readbraw    0  0%
                       writebraw    0  0%
                          writec    0  0%
                       gettattre    0  0%
                       settattre    0  0%
                        lockingX    0  0%
                             IPC  192  1%
                           open2    0  0%
                     find_first2    0  0%
                      find_next2    0  0%
                   query_fs_info    0  0%
                 query_path_info    0  0%
                   set_path_info    0  0%
                 query_file_info    0  0%
                   set_file_info    0  0%
                     create_dir2    0  0%
                    Dfs_referral    0  0%
                      Dfs_report    0  0%
                            echo    0  0%
                      writeclose    0  0%
                           openX    0  0%
                           readX    0  0%
                          writeX    0  0%
                       findclose    0  0%
                            tcon    0  0%
                            tdis   33  0%
                         negprot   39  0%
                           login    4  0%
                          logout    0  0%
                           tconX    2  0%
                         dskattr    0  0%
                          search    0  0%
                          fclose    0  0%
                       NTCreateX   16  0%
                   NTTransCreate    0  0%
                    NTTransIoctl    0  0%
                   NTTransNotify    0  0%
                   NTTransSetSec    0  0%
                 NTTransQuerySec    0  0%
                NTNamedPipeMulti    0  0%
                     NTCancel CN    0  0%
                  NTCancel Other    0  0%
                        SMB2Echo    0  0%
                     SMB2Negprot   41  0%
                SMB2TreeConnnect   62  0%
              SMB2TreeDisconnect   33  0%
                       SMB2Login   42  0%
                      SMB2Create 2163  6%
                        SMB2Read17042 44%
                       SMB2Write12915 34%
                        SMB2Lock    0  0%
                      SMB2Unlock    0  0%
                  SMB2OplkBrkAck    0  0%
                      SMB2ChgNfy   86  0%
                       SMB2CLose 1914  5%
                       SMB2Flush    3  0%
                      SMB2Logout   11  0%
                      SMB2Cancel   59  0%
                   SMB2IPCCreate    7  0%
                     SMB2IPCRead    7  0%
                    SMB2IPCWrite    7  0%
                    SMB2QueryDir 1500  4%
          SMB2QueryFileBasicInfo    0  0%
           SMB2QueryFileStndInfo    0  0%
            SMB2QueryFileIntInfo   45  0%
             SMB2QueryFileEAInfo   55  0%
            SMB2QueryFileFEAInfo    0  0%
           SMB2QueryFileModeInfo    0  0%
            SMB2QueryAltNameInfo    0  0%
         SMB2QueryFileStreamInfo   21  0%
            SMB2QueryNetOpenInfo  209  1%
            SMB2QueryAttrTagInfo    0  0%
             SMB2QueryAccessInfo    0  0%
        SMB2QueryFileUnsupported    0  0%
            SMB2QueryFileInvalid    0  0%
              SMB2QueryFSVolInfo   70  0%
             SMB2QueryFSSizeInfo   10  0%
              SMB2QueryFSDevInfo    0  0%
             SMB2QueryFSAttrInfo   70  0%
           SMB2QueryFSFullSzInfo   38  0%
            SMB2QueryFSObjIdInfo    0  0%
              SMB2QueryFSInvalid    0  0%
           SMB2QuerySecurityInfo  106  0%
                SMB2SetBasicInfo   30  0%
               SMB2SetRenameInfo   25  0%
             SMB2SetFileLinkInfo    0  0%
             SMB2SetFileDispInfo   14  0%
               SMB2SetFullEAInfo    0  0%
                 SMB2SetModeInfo    0  0%
                SMB2SetAllocInfo   13  0%
                  SMB2SetEOFInfo   18  0%
              SMB2SetUnsupported    0  0%
              SMB2SetInfoInvalid    0  0%
             SMB2SetSecurityInfo   22  0%
         SMB2FsctlPipeTransceive 1331  3%
               SMB2FsctlPipePeek    0  0%
          SMB2FsctlEnumSnapshots    0  0%
           SMB2FsctlDfsReferrals    4  0%
              SMB2FsctlSetSparse    0  0%
            SMB2FsctlSecureShare    0  0%
        SMB2FsctlFileUnsupported  127  0%
         SMB2FsctlIpcUnsupported    0  0%
                     cancel lock    0
                       wait lock    0
                   copy to align    0
                    alignedSmall 2250
                    alignedLarge 2272
                 alignedSmallRel    0
                 alignedLargeRel    0
                   FidHashAllocs    0
                   TidHashAllocs    0
                   UidHashAllocs    0
                        mbufWait    0
                         nbtWait    0
                        pBlkWait    0
                BackToBackCPWait    0
                         cwaWait    0
               short msg prevent    2
                     multipleVCs    0
                     SMB signing   41
                mapped null user    0
                      PDCupcalls    0
                       nosupport    0
                  read pipe busy    0
                 write pipe busy    0
                 trans pipe busy    0
                read pipe broken    0
               write pipe broken    0
               trans pipe broken    0
                 queued writeraw    0
                  nbt disconnect   16
                  smb disconnect   17
                  dup disconnect    0
              OpLkBkXorBatchToL2    0
            OpLkBkXorBatchToNone    0
                  OpLkBkL2ToNone    0
                OpLkBkNoBreakAck    0
              OpLkBkNoBreakAck95    0
              OpLkBkNoBreakAckNT    0
                OpLkBkIgnoredAck    0
            OpLkBkWaiterTimedOut    0
              OpLkBkDelayedBreak    0
             SharingErrorRetries    0
                    FoldAttempts    0
                     FoldRenames    0
              FoldRenameFailures    0
                   FoldOverflows    0
                  FoldDuplicates    0
                 FoldWAFLTooBusy    0
                 NoAllocCredStat    0
               RetryRPCcollision    0
                    TconCloseTID    0
                 GetNTAPExtAttrs    0
                 SetNTAPExtAttrs    0
                      SearchBusy    0
                  ChgNfyNoMemory    0
                  ChgNfyNewWatch   67
                 ChgNfyLastWatch   57
               UsedMIDTblCreated    2
             UnusedMIDTblCreated    0
               InvalidMIDRejects    0
            SMB2InvalidSignature    0
       SMB2DurableCreateReceived 2126
      SMB2DurableCreateSucceeded  227
      SMB2DurableReclaimReceived    0
     SMB2DurableReclaimSucceeded    0
      SMB2DurableHandlePreserved    0
         SMB2DurableHandlePurged    0
        SMB2DurableHandleExpired    0
                 SMB2FileDirInfo    0
             SMB2FileFullDirInfo    0
           SMB2FileIdFullDirInfo    0
             SMB2FileBothDirInfo    0
           SMB2FileIdBothDirInfo  750
               SMB2FileNamesInfo    0
          SMB2FileDirUnsupported    0
                   SMB2QueryInfo  624
                     SMB2SetInfo  122
                       SMB2Ioctl 1462
          SMB2RelatedCompRequest 1018
        SMB2UnRelatedCompRequest    0
                 SMB2FileRequest36520
                 SMB2PipeRequest 1390
              SMB2_1_LeaseBreaks    0
            SMB2_1_LeaseUpgrades    0
        SMB2_1_LeaseBreakExcuses  135
    SMB2_1_LeaseBreakAckTimeouts    0
        SMB2_1_HandleLeaseBreaks    0
        SMB2_1_LeaseBreaksToNone    0
    SMB2_1_LeaseBreakAcksIgnored    0
SMB2_1_StatLeaseWorkObjAllocFail    0
                   SMB2nosupport   25

Max Multiplex = 50, Max pBlk Exhaust = 0, Max pBlk Reserve Exhaust = 0

Max FIDs = 22, Max FIDs on one tree = 13

Max Searches on one tree = 0, Max Core Searches on one tree = 0

Max sessions = 17

Max trees = 16

Max shares = 6

Max session UIDs = 1, Max session TIDs = 2

Max locks = 28

Max credentials = 16

Max group SIDs per credential = 71

Max pBlks = 1024 Current pBlks = 1024 Num Logons = 0

Max reserved pBlks = 32 Current reserved pBlks = 32

Max gAuthQueue depth     = 4

Max gSMBBlockingQueue depth  = 1

Max gSMBTimerQueue depth = 5
Max gSMBAlfQueue depth   = 1

Max gSMBRPCWorkerQueue depth = 1

Max gOffloadQueue depth  = 2

Max gSMB2SigningQueue depth  = 0

Local groups: builtins = 6, user-defined = 1, SIDs = 4

RPC group count = 10, RPC group active count = 1

Max Watched Directories = 11, Current Watched Directories = 10

Max Pending ChangeNotify Requests = 10, Current Pending ChangeNotify Requests = 9

Max Pending DeleteOnClose Requests = 3072, Current Pending DeleteOnClose Requests = 0

and cifs stat for second controller (bad)

                         reject    0  0%
                           mkdir    0  0%
                           rmdir    0  0%
                            open    0  0%
                          create    0  0%
                           close    0  0%
                         X&close    0  0%
                           flush    0  0%
                         X&flush    0  0%
                          delete    0  0%
                          rename    0  0%
                        NTRename    0  0%
                          getatr    0  0%
                          setatr    0  0%
                            read    0  0%
                          X&read    0  0%
                           write    0  0%
                         X&write    0  0%
                            lock    0  0%
                          unlock    0  0%
                           mknew    0  0%
                          chkpth    0  0%
                            exit    0  0%
                           lseek    0  0%
                        lockread    0  0%
                      X&lockread    0  0%
                     writeunlock    0  0%
                        readbraw    0  0%
                       writebraw    0  0%
                          writec    0  0%
                       gettattre    0  0%
                       settattre    0  0%
                        lockingX    0  0%
                             IPC  192  1%
                           open2    0  0%
                     find_first2    0  0%
                      find_next2    0  0%
                   query_fs_info    0  0%
                 query_path_info    0  0%
                   set_path_info    0  0%
                 query_file_info    0  0%
                   set_file_info    0  0%
                     create_dir2    0  0%
                    Dfs_referral    0  0%
                      Dfs_report    0  0%
                            echo    0  0%
                      writeclose    0  0%
                           openX    0  0%
                           readX    0  0%
                          writeX    0  0%
                       findclose    0  0%
                            tcon    0  0%
                            tdis   33  0%
                         negprot   30  0%
                           login    4  0%
                          logout    0  0%
                           tconX    2  0%
                         dskattr    0  0%
                          search    0  0%
                          fclose    0  0%
                       NTCreateX   16  0%
                   NTTransCreate    0  0%
                    NTTransIoctl    0  0%
                   NTTransNotify    0  0%
                   NTTransSetSec    0  0%
                 NTTransQuerySec    0  0%
                NTNamedPipeMulti    0  0%
                     NTCancel CN    0  0%
                  NTCancel Other    0  0%
                        SMB2Echo    0  0%
                     SMB2Negprot   36  0%
                SMB2TreeConnnect   61  0%
              SMB2TreeDisconnect   33  0%
                       SMB2Login   45  0%
                      SMB2Create 2310  8%
                        SMB2Read18405 64%
                       SMB2Write  339  1%
                        SMB2Lock    1  0%
                      SMB2Unlock    0  0%
                  SMB2OplkBrkAck    0  0%
                      SMB2ChgNfy   61  0%
                       SMB2CLose 2142  7%
                       SMB2Flush    2  0%
                      SMB2Logout    4  0%
                      SMB2Cancel  385  1%
                   SMB2IPCCreate   23  0%
                     SMB2IPCRead   23  0%
                    SMB2IPCWrite   23  0%
                    SMB2QueryDir 2778 10%
          SMB2QueryFileBasicInfo    0  0%
           SMB2QueryFileStndInfo    0  0%
            SMB2QueryFileIntInfo    8  0%
             SMB2QueryFileEAInfo   18  0%
            SMB2QueryFileFEAInfo    0  0%
           SMB2QueryFileModeInfo    0  0%
            SMB2QueryAltNameInfo    0  0%
         SMB2QueryFileStreamInfo   18  0%
            SMB2QueryNetOpenInfo  111  0%
            SMB2QueryAttrTagInfo    0  0%
             SMB2QueryAccessInfo    0  0%
        SMB2QueryFileUnsupported    0  0%
            SMB2QueryFileInvalid    0  0%
              SMB2QueryFSVolInfo  133  0%
             SMB2QueryFSSizeInfo    8  0%
              SMB2QueryFSDevInfo    0  0%
             SMB2QueryFSAttrInfo  133  0%
           SMB2QueryFSFullSzInfo   11  0%
            SMB2QueryFSObjIdInfo    0  0%
              SMB2QueryFSInvalid    0  0%
           SMB2QuerySecurityInfo   77  0%
                SMB2SetBasicInfo   24  0%
               SMB2SetRenameInfo   17  0%
             SMB2SetFileLinkInfo    0  0%
             SMB2SetFileDispInfo   12  0%
               SMB2SetFullEAInfo    0  0%
                 SMB2SetModeInfo    0  0%
                SMB2SetAllocInfo    3  0%
                  SMB2SetEOFInfo   12  0%
              SMB2SetUnsupported    0  0%
              SMB2SetInfoInvalid    0  0%
             SMB2SetSecurityInfo   16  0%
         SMB2FsctlPipeTransceive 1287  4%
               SMB2FsctlPipePeek    0  0%
          SMB2FsctlEnumSnapshots    0  0%
           SMB2FsctlDfsReferrals   10  0%
              SMB2FsctlSetSparse    0  0%
            SMB2FsctlSecureShare    0  0%
        SMB2FsctlFileUnsupported   36  0%
         SMB2FsctlIpcUnsupported   21  0%
                     cancel lock    0
                       wait lock    0
                   copy to align    0
                    alignedSmall 2847
                    alignedLarge 2389
                 alignedSmallRel    0
                 alignedLargeRel    0
                   FidHashAllocs    0
                   TidHashAllocs    0
                   UidHashAllocs    0
                        mbufWait    0
                         nbtWait    0
                        pBlkWait    0
                BackToBackCPWait    0
                         cwaWait    0
               short msg prevent    5
                     multipleVCs    0
                     SMB signing   32
                mapped null user    0
                      PDCupcalls    0
                       nosupport    0
                  read pipe busy    0
                 write pipe busy    0
                 trans pipe busy    0
                read pipe broken    0
               write pipe broken    0
               trans pipe broken    0
                 queued writeraw    0
                  nbt disconnect   13
                  smb disconnect   21
                  dup disconnect    0
              OpLkBkXorBatchToL2    0
            OpLkBkXorBatchToNone    0
                  OpLkBkL2ToNone    0
                OpLkBkNoBreakAck    0
              OpLkBkNoBreakAck95    0
              OpLkBkNoBreakAckNT    0
                OpLkBkIgnoredAck    0
            OpLkBkWaiterTimedOut    0
              OpLkBkDelayedBreak    0
             SharingErrorRetries    0
                    FoldAttempts    0
                     FoldRenames    0
              FoldRenameFailures    0
                   FoldOverflows    0
                  FoldDuplicates    0
                 FoldWAFLTooBusy    0
                 NoAllocCredStat    0
               RetryRPCcollision    0
                    TconCloseTID    0
                 GetNTAPExtAttrs    0
                 SetNTAPExtAttrs    0
                      SearchBusy    0
                  ChgNfyNoMemory    0
                  ChgNfyNewWatch   50
                 ChgNfyLastWatch   47
               UsedMIDTblCreated    6
             UnusedMIDTblCreated    0
               InvalidMIDRejects    0
            SMB2InvalidSignature    0
       SMB2DurableCreateReceived 2286
      SMB2DurableCreateSucceeded  135
      SMB2DurableReclaimReceived    0
     SMB2DurableReclaimSucceeded    0
      SMB2DurableHandlePreserved    0
         SMB2DurableHandlePurged    0
        SMB2DurableHandleExpired    0
                 SMB2FileDirInfo    0
             SMB2FileFullDirInfo   12
           SMB2FileIdFullDirInfo    0
             SMB2FileBothDirInfo    5
           SMB2FileIdBothDirInfo 1414
               SMB2FileNamesInfo    0
          SMB2FileDirUnsupported    0
                   SMB2QueryInfo  517
                     SMB2SetInfo   84
                       SMB2Ioctl 1354
          SMB2RelatedCompRequest 1579
        SMB2UnRelatedCompRequest    0
                 SMB2FileRequest27016
                 SMB2PipeRequest 1548
              SMB2_1_LeaseBreaks    1
            SMB2_1_LeaseUpgrades    0
        SMB2_1_LeaseBreakExcuses   92
    SMB2_1_LeaseBreakAckTimeouts    0
        SMB2_1_HandleLeaseBreaks    0
        SMB2_1_LeaseBreaksToNone    1
    SMB2_1_LeaseBreakAcksIgnored    0
SMB2_1_StatLeaseWorkObjAllocFail    0
                   SMB2nosupport  128

Max Multiplex = 50, Max pBlk Exhaust = 0, Max pBlk Reserve Exhaust = 0

Max FIDs = 18, Max FIDs on one tree = 14

Max Searches on one tree = 0, Max Core Searches on one tree = 0

Max sessions = 16

Max trees = 18

Max shares = 7

Max session UIDs = 1, Max session TIDs = 4

Max locks = 25

Max credentials = 15

Max group SIDs per credential = 71

Max pBlks = 1024 Current pBlks = 1024 Num Logons = 0

Max reserved pBlks = 32 Current reserved pBlks = 32

Max gAuthQueue depth     = 2

Max gSMBBlockingQueue depth  = 1

Max gSMBTimerQueue depth = 6
Max gSMBAlfQueue depth   = 1

Max gSMBRPCWorkerQueue depth = 1

Max gOffloadQueue depth  = 2

Max gSMB2SigningQueue depth  = 0

Local groups: builtins = 6, user-defined = 1, SIDs = 4

RPC group count = 10, RPC group active count = 1

Max Watched Directories = 6, Current Watched Directories = 3

Max Pending ChangeNotify Requests = 4, Current Pending ChangeNotify Requests = 3

Max Pending DeleteOnClose Requests = 3072, Current Pending DeleteOnClose Requests = 0

On the second controller I'm specifically doing the test on a newly created volume without dedup. Tried already to disable vscan but changes nothing, besides the first controller performs great with dedup and vscan enabled, as I said all settings the same.

Doing a quick packet sniff on the client I see that after a couple of seconds in a file transfer sessions there are only read requests from the client and no responses from the filer and then it responds again and then the same all over again.

Any help appreciated.

Re: FAS2220 CIFS 2 controllers same settings big performance difference

how much disks do the aggregates have? is one bigger than the other?

sysconfig -r

Re: FAS2220 CIFS 2 controllers same settings big performance difference

Actually they are exactly the same:

First

Aggregate aggr0 (online, raid4) (block checksums)

  Plex /aggr0/plex0 (online, normal, active)

    RAID group /aggr0/plex0/rg0 (normal, block checksums)

      RAID Disk Device          HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Phys (MB/blks)

      --------- ------          ------------- ---- ---- ---- ----- --------------    --------------

      parity    0a.00.2         0a    0   2   SA:A   0  FSAS  7200 3807816/7798408704 3815447/7814037168

      data      0a.00.4         0a    0   4   SA:A   0  FSAS  7200 3807816/7798408704 3815447/7814037168

      data      0a.00.6         0a    0   6   SA:A   0  FSAS  7200 3807816/7798408704 3815447/7814037168

      data      0a.00.8         0a    0   8   SA:A   0  FSAS  7200 3807816/7798408704 3815447/7814037168

      data      0a.00.10        0a    0   10  SA:A   0  FSAS  7200 3807816/7798408704 3815447/7814037168

Pool1 spare disks (empty)

Pool0 spare disks

RAID Disk       Device          HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Phys (MB/blks)

---------       ------          ------------- ---- ---- ---- ----- --------------    --------------

Spare disks for block checksum

spare           0a.00.0         0a    0   0   SA:A   0  FSAS  7200 3807816/7798408704 3815447/7814037168 (not zeroed)

Partner disks

RAID Disk       Device          HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Phys (MB/blks)

---------       ------          ------------- ---- ---- ---- ----- --------------    --------------

partner         0b.00.11        0b    0   11  SA:B   0  FSAS  7200 0/0               3815447/7814037168

partner         0b.00.5         0b    0   5   SA:B   0  FSAS  7200 0/0               3815447/7814037168

partner         0b.00.9         0b    0   9   SA:B   0  FSAS  7200 0/0               3815447/7814037168

partner         0b.00.7         0b    0   7   SA:B   0  FSAS  7200 0/0               3815447/7814037168

partner         0b.00.3         0b    0   3   SA:B   0  FSAS  7200 0/0               3815447/7814037168

partner         0b.00.1         0b    0   1   SA:B   0  FSAS  7200 0/0               3815447/7814037168

Second

Aggregate aggr0 (online, raid4) (block checksums)

  Plex /aggr0/plex0 (online, normal, active)

    RAID group /aggr0/plex0/rg0 (normal, block checksums)

      RAID Disk Device          HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Phys (MB/blks)

      --------- ------          ------------- ---- ---- ---- ----- --------------    --------------

      parity    0a.00.3         0a    0   3   SA:B   0  FSAS  7200 3807816/7798408704 3815447/7814037168

      data      0a.00.5         0a    0   5   SA:B   0  FSAS  7200 3807816/7798408704 3815447/7814037168

      data      0a.00.7         0a    0   7   SA:B   0  FSAS  7200 3807816/7798408704 3815447/7814037168

      data      0a.00.9         0a    0   9   SA:B   0  FSAS  7200 3807816/7798408704 3815447/7814037168

      data      0a.00.11        0a    0   11  SA:B   0  FSAS  7200 3807816/7798408704 3815447/7814037168

Pool1 spare disks (empty)

Pool0 spare disks

RAID Disk       Device          HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Phys (MB/blks)

---------       ------          ------------- ---- ---- ---- ----- --------------    --------------

Spare disks for block checksum

spare           0a.00.1         0a    0   1   SA:B   0  FSAS  7200 3807816/7798408704 3815447/7814037168 (not zeroed)

Partner disks

RAID Disk       Device          HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Phys (MB/blks)

---------       ------          ------------- ---- ---- ---- ----- --------------    --------------

partner         0b.00.10        0b    0   10  SA:A   0  FSAS  7200 0/0               3815447/7814037168

partner         0b.00.6         0b    0   6   SA:A   0  FSAS  7200 0/0               3815447/7814037168

partner         0b.00.0         0b    0   0   SA:A   0  FSAS  7200 0/0               3815447/7814037168

partner         0b.00.8         0b    0   8   SA:A   0  FSAS  7200 0/0               3815447/7814037168

partner         0b.00.2         0b    0   2   SA:A   0  FSAS  7200 0/0               3815447/7814037168

partner         0b.00.4         0b    0   4   SA:A   0  FSAS  7200 0/0               3815447/7814037168

Re: FAS2220 CIFS 2 controllers same settings big performance difference

then I don't have an idea why this happens

I recommend to fetch perfstats, open a case at Netapp and let them analyse the stats.

Re: FAS2220 CIFS 2 controllers same settings big performance difference

Mundane question - are the options for TCP Window Size set to the same values on both controllers?

filer>options cifs.tcp_window_size

Believe the recommendation is to ensure it's set to at least 64,240 (and I think as of ONTAP 8.2.1 the default is set to that).

It can go as high as 8,388,608, however.

Just something to check.

Re: FAS2220 CIFS 2 controllers same settings big performance difference

I have already tried to changed the tcp window size but nothing changed. The issue occurs regardless of this setting.

Probably will raise a support ticket.