On Sun Ultra 20 and Sun Fire X2100 systems with Opteron RevE CPU running Linux Operating Systems and configured with at least 4 GB unbuffered memory (or more), a "silent data corruption" issue may occur.

This issue can occur on the following platforms:

• Sun Ultra 20 without BIOS version 2.2.9
• Sun Fire X2100 without BIOS version 1.1.7

with the following configuration:

1. Opteron RevE CPU
2. 4GB (or more) unbuffered memory
3. running any Linux Distribution like RHEL, SuSE etc.

Note: Systems with 1GB or 2GB unbuffered memory, and other Operating Systems (i.e. Sun Solaris) are not known to be affected by this issue.

The data corruption is typically a 4K block that is completely "nulled out", and sometimes random data are inside this 4K block. This may happen randomly to any files of any size, and there is no indication that data corruption has occurred.

To work around the described issue, add the kernel parameter "iommu=soft" to the kernel command line in the grub boot loader configuration "/boot/grub/grub.conf".

Note: Allowing the Linux Kernel to do the software bounce buffering has a performance hit of 15% to 20% for I/O operations.

This issue is addressed on the following platforms:

• Sun Ultra 20 with BIOS version 2.2.9 or later
• Sun Fire X2100 with BIOS version 1.1.7 or later

The BIOS versions can be upgraded from the "Tools & Drivers" CD V1.7, available for download at:

For Ultra 20:

http://www.sun.com/desktop/workstation/ultra20/downloads.jsp

For Sun Fire X2100:

http://www.sun.com/servers/entry/x2100/downloads.jsp

• Updated Contributing Factors and Resolution sections
• State: Resolved

This solution has no attachment