Adaptive Server requires several database devices. Table 2-13 below shows baseline values for each of the devices. See the release bulletin for any last-minute changes to these values.
Device |
Purpose |
Minimum size |
Minimum recommended size |
|---|---|---|---|
master |
Stores system databases |
14MB for 2K pages 27MB for 4K pages 50MB for 8K pages 105MB for 16K pages |
30MB 60MB 120MB 240MB |
sysprocsdev (also called the sybsystemprocs device) |
Stores the sybsystemprocs database |
100MB |
100MB (plus any space for holding stored procedures that you have created) |
sybsystemdb |
Transaction processing |
4MB |
5 – 20MB |
sybsecurity (optional) |
Required for auditing |
5MB |
7MB; more for specialized auditing |
For all databases you can use either a raw partition or a file.
NFS mounted devices have been tested on Solaris, HP/UX, IBM AIX, Windows NT, Linux, and SGI.
Previous versions of Adaptive Server performed buffered
writes to file devices, which does not ensure recoverability. Starting
in version 12.0, the default for writes to file systems is unbuffered,
so files are now acceptable as database devices.
Do not run Adaptive Server on network-mounted devices, such as NFS-mounted files, for these reasons:
Network problems can cause serious data integrity problems because the network lies between Adaptive Server and the devices on which it writes.
If the remote machine is down when you restart Adaptive Server, and database devices cannot be activated, automatic recovery fails.
Adaptive Server is suspended when the remote machine or network is down.
You may need to repartition the disk you choose. Contact your operating system administrator for assistance.
When preparing a raw partition device, follow these guidelines:
Do not initialize a database device on the partition that contains your Sybase installation software. Doing so destroys all existing files on that partition.
A raw partition designated for use by Sybase cannot be mounted for use by the operating system for any other purpose, such as for file systems or swap space.
After a Sybase configuration utility or the disk init command has initialized a portion of a partition as a database device, the entire partition cannot be used for any other purpose. Any space left on the partition beyond the size specified for the device becomes inaccessible, unless you drop and re-create the device.
For best performance, place the Sybase software and all disk devices, including the master device, on the same machine.
Place the database device on a character device, because the Adaptive Server recovery system needs unbuffered system I/O. The character devices are in the /dev/rdsk directory.
To determine whether a device is a block device or a character device, run this command on the device filename:
ls -l
“b” (block) or “c” (character) appears in the left-most column.
Choosing a raw partition
Determine which raw partitions are available.
Determine the sizes of the raw partitions.
From the list of available raw partitions, select a raw partition for each device, based on the size recommendations in Table 2-13.
Verify that the device is a character device.
Verify with the operating System Administrator that the partition you have chosen is available.
The System Administrator should mark this partition in /etc/fstab as being of the rawdata datatype
Make sure the “sybase” user has read and write privileges to the raw partition.
For more information on choosing a raw partition, see
your operating system documentation.
