Novell Open Enterprise Server 2 Benutzerhandbuch
Using Software RAID0 Devices to Enhance Disk I/O Performance
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Using Software RAID0 Devices to
Enhance Disk I/O Performance
Enhance Disk I/O Performance
If your disk response time is slow for heavily used volumes, you can improve disk I/O performance
by using a software RAID0 device for the volume. Even though the NetWare
by using a software RAID0 device for the volume. Even though the NetWare
®
Traditional File
System volumes can comprise segments from multiple disks, the disks are not forced to distribute
data evenly across the member disks. A RAID0 device evenly stripes data across its disks.
data evenly across the member disks. A RAID0 device evenly stripes data across its disks.
This section discusses the following:
6.1 Planning Your Software RAID0 Device
Striping is a software RAID technique that writes data concurrently to multiple separate devices.
Consider the following guidelines before creating your RAID 1 device:
Consider the following guidelines before creating your RAID 1 device:
A segment is the amount of storage space used from each disk you plan to use in the software
RAID device. A software RAID0 device can accommodate 2 to14 segments.
RAID device. A software RAID0 device can accommodate 2 to14 segments.
A stripe is the amount of data the file system places on one device before moving to the next
device. The stripe size ranges from 4 KB to 256 KB, in increments of 2 KB. The default stripe
size is 64 KB.
device. The stripe size ranges from 4 KB to 256 KB, in increments of 2 KB. The default stripe
size is 64 KB.
Each segment in the software RAID0 configuration should come from a different device. You
can obtain segments from the same device, but this can severely impede the performance of
your file system on the RAID.
can obtain segments from the same device, but this can severely impede the performance of
your file system on the RAID.
It is best to use segments of the same size when you create your RAID device. The size of each
segment must be compatible in data area size with other segments you plan to use. The
minimum segment size is 100 KB. The maximum size must not be more than 120 MB larger
than the size of other partitions. The size the RAID pulls from each segment is equivalent to the
size of its smallest member segment.
segment must be compatible in data area size with other segments you plan to use. The
minimum segment size is 100 KB. The maximum size must not be more than 120 MB larger
than the size of other partitions. The size the RAID pulls from each segment is equivalent to the
size of its smallest member segment.
All member segments in the software RAID0 device must have the same sharable status. Either
all are sharable for clustering, or all are not. Set the segment’s disk as Sharable or Not
Shareable before you build the RAID.
all are sharable for clustering, or all are not. Set the segment’s disk as Sharable or Not
Shareable before you build the RAID.
If one of the member disks fails, all volumes on the RAID device become unavailable. After
you replace the disk, you must restore each volume from backup media. Each volume’s data
must be restriped across all segments in the RAID before you can use the volume again.
you replace the disk, you must restore each volume from backup media. Each volume’s data
must be restriped across all segments in the RAID before you can use the volume again.
If one of the member disks fails, the entire volume becomes unavailable. Therefore, you should
mirror or duplex volumes built on RAID0 devices. To mirror the software RAID0 devices, the
devices in the mirror must have no disks in common. This configuration creates a software
RAID 10 Traditional volume.
mirror or duplex volumes built on RAID0 devices. To mirror the software RAID0 devices, the
devices in the mirror must have no disks in common. This configuration creates a software
RAID 10 Traditional volume.