Limitations Of This Release - Dell DX6000G Release Notes

• The CNS garbage collection process has been enhanced to prioritize garbage collection for large
XML containers with a high percentage of historical data for faster memory reclamation.

1.5. Limitations of this Release

These are the known issues and operational limitations that exist in this release of CFS 2.5:
• Membership in a Large Number of ACL Groups Users with memberships in a large number of
ACLs groups (>31) may experience permission issues when accessing directories.
• Zeroconf Node Discovery If using Zeroconf for discovering the list of DX Storage nodes and
using a cluster name with periods in it, the periods must be replaced with underscores to ensure
proper node discovery.
• Red Hat 'hugepages' Compatibility The recently added Red Hat 'hugepages' feature has
been found to be incompatible with CFS and other applications, often resulting in kernel hangs
particularly under high stress scenarios. As a result it is highly recommended that huge pages
be disabled. Please reference the 'Installation' chapter of the Setup and Configuration Guide for
complete details.
• NFS v4 Compatibility Files written to CFS via NFS version 4 may not get all their permissions
properly set, and NFS v4 is therefore not supported. NFS version 3 is supported.
• Firewall Rules for mDNS RHEL 6 firewall blocks mDNS lookups by default. In order to use the
Zeroconf configuration to find DX Storage nodes, customers must enable mDNS in the firewall.
Steps:
1. From a root command shell run: system-config-firewall-tui
2. The "Firewall: [*]" checkbox should be checked with the spacebar to enable it.
3. Tab to the "Customize" button, cursor down to "Multicast DNS (mDNS)" and use the
spacebar to enable it.
4. Click Tab or OK on the remaining screens and then "Yes" on the final Warning screen .
• Passwords when using DX Storage 4.x and CFS Installations running DX Storage 4.x should
use clear text administrative passwords, not hashed ones, to ensure CFS is able to write
all journals and CNS containers using replicate on write for maximum data protection. After
upgrading to DX Storage 5.0 use of hashed passwords can be resumed.
• Name Space Restarts Restarts of the Cluster Name Space may become increasingly longer as
the number of objects in the name space grows over time.
• SELinux Mount Interference on Reboot SELinux may prevent files shares from mounting
after a reboot. To disable SELinux on a test environment, edit the /etc/selinux/config file and set
'SELINUX=disabled'.
• NFS Stale File Handle Errors Users may occasionally receive 'Stale NFS file handle' errors in an
NFS client when writing or reading to CFS. To ensure all data is transmitted correctly, files should
be closed and reopened when one of these errors is encountered.
• DF Inode Reporting CFS does not report inode information in response to a 'df -i' command to
the filesystem. Applications needing to determine available space should query based on blocks
rather than inodes.
Copyright © 2011 Caringo, Inc.
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Version 2.6.1
March 2011