Chapter 24. Storage

e2fsprogs component
The e4defrag utility in the e2fsprogs package is not supported in Red Hat Enterprise Linux 7.0, and is scheduled to be removed in Red Hat Enterprise Linux 7.1.
xfsprogs component
If XFS metadata checksums are enabled specifying the -m crc=1 option to the mkfs.xfs command, the kernel prints the following warning message when the file system is mounted:
Version 5 superblock detected. This kernel has EXPERIMENTAL support enabled!
Use of these features in this kernel is at your own risk!
Note that this CRC functionality is available for testing in Red Hat Enterprise Linux 7.0 and is planned to be fully supported in Red Hat Enterprise Linux 7.1.
cryptsetup component, BZ#883941
When the systemd daemon parses the crypttab file in case of a non-LUKS device for swap with a random key, it uses the ripemd160 hash by default, which is not allowed in FIPS mode. To work around this problem, add the hash= setting with an algorithm approved for FIPS to the particular crypttab line. For example: swap /dev/sda7 /dev/urandom swap,hash=sha1.
lvm2 component, BZ#1083633
If the kernel thin provisioning code detects a device failure or runs out of metadata space, it sets a flag on the device to indicate that it needs to be checked. Currently, LVM tools do not perform this check automatically. To work around this problem, execute the thin_check --clear-needs-check-flag command to perform the check and remove the flag. Then run the thin_repair command if necessary. Alternatively, you can add --clear-needs-check-flag to thin_check_options in the global section of the /etc/lvm.conf configuration file to run the check automatically.
device-mapper-multipath component, BZ#1066264
In Red Hat Enterprise Linux 7, the behavior of the kpartx utility has been changed, so it no longer adds the letter p as a delimiter between a device name and a partition suffix unless the device name ends with a digit. When a device is renamed using the multipath utility, the previous device name is simply replaced by a new name while the suffix stays unchanged, regardless of the delimiter. Consequently, the kpartx behavior is not followed, and changing device names ending in a digit to names ending in a letter, or the other way round, works incorrectly when using multipath to rename devices. To work around this problem, choose one of the following three options:
  • Remove the multipathd daemon and add the devices again;
  • Remove the devices manually by using the kpartx -d command and then add them by running the partx -a command;
  • Rename the devices by using the kpartx -p p command for device names that are supposed to contain the delimiter and they do not, and the kpartx -p "" command in cases when the delimiter is used redundantly.
snapper component, BZ#1071973
The empty-pre-post cleanup algorithm, which is used for deleting pre-post pairs of file system snapshots with empty diffs, does not work in Red Hat Enterprise Linux 7. To work around this problem, remove empty pre-post snapshot couples manually by using the delete command.
kernel component, BZ#1084859
The bigalloc feature for the ext4 file systems, which enables ext4 to use clustered allocation, is not supported in Red Hat Enterprise Linux 7.
lvm2 component, BZ#1083835
Placing the /boot partition on an LVM volume is not supported. Placing the /boot partition on a Btrfs subvolume is not supported either.
nfs-utils component, BZ#1082746
While the rpc.svcgssd binary is included in the nfs-utils package in Red Hat Enterprise Linux 7.0, its use in new deployments is discouraged in favor of gssproxy. The rpc.svcgssd binary may be removed in later Red Hat Enterprise Linux 7 releases.
kernel component, BZ#1061871, BZ#1201247
When a storage array returns a CHECK CONDITION status but the sense data is invalid, the Small Computer Systems Interface (SCSI) mid-layer code retries the I/O operation. If subsequent I/O operations receive the same result, I/O operations are retried indefinitely. For this bug, no workaround is currently available.