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Raid Level
5
6.1.5 Configuration Options for RAIDs
In EVMS management tools, the following RAID configuration options are provided:
Configuration Options in EVMS
Table 6-5
Option
Spare Disk
Chunk Size (KB)
RAID Level
RAID Algorithm
6.1.6 Interoperability Issues
Linux software RAID cannot be used underneath clustered file systems because it does not support
concurrent activation. If you want RAID and OCFS2, you need the RAID to be handled by the
storage subsystem.
WARNING: Activating Linux software RAID devices concurrently on multiple servers can result
in data corruption or inconsistencies.
78
SLES 10 SP2: Storage Administration Guide
Number of Disk Failures Tolerated
1
Description
For RAIDs 1, 4, and 5, you can optionally specify a device, segment, or
region to use as the replacement for a failed disk (the member device,
segment, or region). On failure, the spare disk automatically replaces the
failed disk, then reconstructs the data.
However, if the parity disk fails on a RAID 5, parity cannot be reconstructed.
For RAIDs 0, 4, or 5, specify the stripe size in KB.
Consider the intended use of the RAID, such as the file system block size,
the applications used, and the actual data (file sizes and typical reads and
writes). A typical write size for large files is 128 KB.
Default: 32 KB
Range: 4 KB to 4096 KB, in powers of 2.
If you selected MD RAID 4/5 Region Manager, specify RAID 4 or RAID 5
(default).
For RAID 5, specify one of the following algorithms to use for striping and
distributing parity on the disk.
Left Asymmetric
Left Symmetric (Default, fastest performance for large reads)
Right Asymmetric
Right Symmetric
Data Redundancy
Distributed parity to reconstruct data and
parity on the failed disk.
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Troubleshooting
