Networking Updates; Filesystems And Storage Updates - Red Hat ENTERPRISE LINUX 5.4 - RELEASE NOTES Release Note

3. Networking Updates

With this update, Generic Receive Offload (GRO) support has been implemented in both the kernel
and the userspace application,
of inbound network connections by reducing the amount of processing done by the Central Processing
Unit (CPU). GRO implements the same technique as the Large Receive Offload (LRO) system, but
can be applied to a wider range of transport layer protocols. GRO support has also been added to a
several network device drivers, including the igb driver for Intel® Gigabit Ethernet Adapters and the
ixgbe driver for Intel 10 Gigabit PCI Express network devices.
The Netfilter framework (the portion of the kernel resposible for network packet filtering) has been
updated with added support for Differentiated Services Code Point (DSCP) values
the bind (Berkeley Internet Name Domain) package provides an implementation of the DNS (Domain
Name System) protocols. Previously, bind did not offer a mechanism to easily distinguish between
requests that will receive authoritative and non-authoritative replies. Consequently, an incorrectly
configured server may have replied to requests that should have been denied. With this update,
bind has been updated, providing the new option allow-query-cache that controls access
to non-authoritative data on a server (for example: cached recursive results and root zone hits).
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(BZ#483708)

4. Filesystems and Storage updates

In the 5.4 update, several significant additions have been made to file systems support. Base Red Hat
Enterprise Linux now includes the Filesystem in Userspace (FUSE) kernel modules and user
space utilities, allowing users to install and run their own FUSE file systems on an unmodified Red Hat
Enterprise Linux kernel
kernel for future product enablement
has been implemented, allowing the physical layout of files to be mapped efficiently. The FIEMAP ioctl
can be used by applications to check for fragmentation of a specific file or to create an optimized copy
of a sparsely allocated file
Additionally, the Common Internet File System (CIFS) has been updated in the kernel
The ext4 file system (included in Red Hat Enterprise Linux as a Technology Preview) has also been
13
(BZ#485315)
updated
In Red Hat Enterprise Linux 5.4, the use of the Global File System 2 (GFS2) as a single server file
system (i.e. not in a clustered environment) is deprecated. Users of GFS2 that do not need high
availability clustering are encouraged to look at migrating to other file systems like the ext3 or xfs
offerings. The xfs file system is specifically targeted at very large file systems (16 TB and above).
Existing users will continue to be supported.
The required semantics indicate that a process which completes a stat, write, stat, should
see a different mtime (time of last modification) on the file in the results from the second stat call
compared to the mtime in the results from the first stat call. File times in NFS are maintained strictly
by the server, so the file mtime will not be updated until the data has been transmitted to the server
7
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=499347
8
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=483708
9
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=457975
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https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=470845
11
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=296951
12
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=465143
13
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=485315
ethtool.((BZ#499347)
9
(BZ#457975)
. Support for the XFS file system has also been added to the
(BZ#470845)
11
(BZ#296951)
.
.
7
) The GRO system increases the performance
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. The FIEMAP input/output control (ioctl) interface
Networking Updates
12
(BZ#465143)
.
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