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Oracle® VM Server for SPARC 3.4 Administration Guide

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Updated: August 2016

Supporting Highly Fragmented I/O Buffers in the Guest Domain

As with other sun4v virtual devices, the vhba module operates on an I/O buffer that is created by higher layers in the software stack. If the I/O buffer is an aggregation of too many fragments of physical memory, the vhba module issues the following fatal warning message when processing the I/O request:

WARNING: ... ldc_mem_bind_hdl: ncookies(max, actual) = (8, 9)

Each physical memory fragment is associated with one cookie. If the actual number of cookies cannot be supported by the maximum number of cookies, the I/O request will fail.

The error message shows the actual number of cookies that are required. To eliminate the error, change the vhba_desc_ncookies value in the /etc/system file, which specifies the number of per-I/O buffer cookies to use, to be at least as large as the actual value. Also, increase the value of the vhba_desc_max_ncookies property, which specifies the allowable maximum number of cookies.

For information about correctly creating or updating /etc/system property values, see Updating Property Values in the /etc/system File.

You then re-create the virtual SCSI HBA's connection by performing a sequence of ldm remove-vhba and ldm add-vhba commands or by rebooting the guest domain.

For example, to set the vhba_desc_max_ncookies property value to 12, add the following line to the /etc/system file:

set vhba:vhba_desc_ncookies = 12