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提高unixware文件系统性能

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1. Add the entry "delaylog=nolog" to the mount options in
/etc/vfstab, for example:
/dev/filesys /dev/rfilesys / vxfs 1 no
delaylog=nolog,mincache=closesync SYS_RANGE_MAXThis will run your filesystem with no transaction logging, making
it difficult to repair in the event of a system crash. However,
it will improve performance, and if the files in this filesystem
are considered to be temporary, then this option can be used.More information on these options are available from the command:man mount_vxfs2. The above online manual page refers to the various "mincache"
options. The default is "mincache=closesync" which is the slowest,
but more reliable method.However, adding the entry "mincache=tmpcache" to the mount options
in /etc/vfstab will cause your filesystem to become unmountable
unless you are using the Advanced VxFS filesystem, On-Line Data
Manager (ODM).NOTES: In order to achIEve the best performance, it"s helpful to look at
the type of disk configurations available:No Raid - Disks independent, no resilienceRaid 0 - Fast as disks are striped.
1 disk min, max depends on controller.
No Fault Tolerance.
Increase disk capacity.Raid 1 - Mirrored disks.
2 disks required.
Fault Tolerance.
Hot Spare available.Raid 5 - Resilience but slow as parity is spread across all the disks.
3 disk min, max depends on controller.
Fault Tolerance.
Hot spare available.Raid 10 - An entire Raid 5 configuration mirrored.
6 disks min, max depends on controller.
Fault Tolerant.
Hot Spare available.
Very slow but Excellent resilience.
Rarely used.Raid 0 1 - Raid 0 configuration but each disk is mirrored.
2 disks min, max depends on controller.
Hot Spare available.
Costly, because if you wanted a 100GB Logical Drive
made from 10GB disks you would need 10 disks for the
100GB, and then a further 10 disks for the mirror.Bus Speed - There are three components: the controller card, PCI bus
inside the server, and the driver for the controller.
All three need to be 64 bit to get true 64 bit,
otherwise there will be a 32 bit bottleneck.Controller - If the controller has memory with a battery backup
then "Write Back" can be used to use the full benefit
of the on-board cache of the controller. The other
option is the "Write Thru" option which is slower
but more reliable.NOTE: If the database used is transaction based, then
data can be written to the disk from the cache during
a boot up if the power had gone down earlier. If the
database is not fully opened then the transaction logs
can get confused.You may want to have separate controllers for separate
filesystem activities.You can also gain performance by ensuring that if the
controller is multi-channel, each logical drive uses
physical disks on the same channel.It is recommended to have a separate controller for
tape(s) and CDROM(s), rather than use the same controller
as the disks. It is also recommended to not have too
many SCSI devices on the same bus.Sizes - You can set the Stripe Size on the controller and the
Block Size of the filesystem to be the same to optimize
performance for large file processing with large
databases, such as Oracle, especially if these databases
are on a separate controller. This would mean increasing
the blocksize of the filesystem, when it is created, to
the same size as the Stripe Size.The larger the block size is, then each file created will
consume that amount in the inode table. For example, a
block size of 8k will consume 8k in the inode table for
each file created. A typical example of this would be an
Oracle database with a 8k block size setting within Oracle"s
configuration. You would make Oracle and the filesystem"s
block size consistent.For some servers you may want to lower the Stripe Size if
lots of small reads and writes are taking place so the
controller is not waiting for its cache to be filled each
time. However, the more read/writes there are, the more

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