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rothermel_john
Contributor
Contributor

SCSI Timout value RDMs in Linux VMs

Are there recommended SCSI timeout values for using raw devices on Linux VMs?

VMware Tools creates a udev rule to change the timeout for devices classified by Vendor "VMware" or attribute "Virtual Disk" from 30 seconds to 180 seconds. This rule does not apply to raw devices since they do not appear as virtual disks to the VM.

[root@server1 ~]# lsscsi

[2:0:0:0]    disk    VMware   Virtual disk     1.0   /dev/sda

[2:0:1:0]    disk    VMware   Virtual disk     1.0   /dev/sdb

[2:0:2:0]    disk    VMware   Virtual disk     1.0   /dev/sdc

[2:0:3:0]    disk    DGC      VRAID            0532  /dev/sdd

[2:0:4:0]    disk    VMware   Virtual disk     1.0   /dev/sde

[2:0:5:0]    disk    VMware   Virtual disk     1.0   /dev/sdf

[2:0:6:0]    disk    VMware   Virtual disk     1.0   /dev/sdg

[3:0:0:0]    disk    DGC      VRAID            0532  /dev/sdh

[3:0:1:0]    disk    DGC      VRAID            0532  /dev/sdi

[3:0:2:0]    disk    DGC      VRAID            0532  /dev/sdj

[root@server1 ~]# find /sys/class/scsi_device/*/device/timeout -exec grep -H . '{}' \;

/sys/class/scsi_device/2:0:0:0/device/timeout:180

/sys/class/scsi_device/2:0:1:0/device/timeout:180

/sys/class/scsi_device/2:0:2:0/device/timeout:180

/sys/class/scsi_device/2:0:3:0/device/timeout:30

/sys/class/scsi_device/2:0:4:0/device/timeout:180

/sys/class/scsi_device/2:0:5:0/device/timeout:180

/sys/class/scsi_device/2:0:6:0/device/timeout:180

/sys/class/scsi_device/3:0:0:0/device/timeout:30

/sys/class/scsi_device/3:0:1:0/device/timeout:30

/sys/class/scsi_device/3:0:2:0/device/timeout:30

Does VMware recommend changing these to 180 as well or leaving them to the default settings? Does it matter if the RDM is in virtual or physical mode? (RDM-V vs. RDM-P)

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