max device size can be created by sybase 15.0

Hi,
Is there any maximum device size in sybase ? or we can create at any size depend on disk size ? Can I initialize a sybase device tp use 150GB in size ?
motioneyeAsked:
Who is Participating?
 
alpmoonCommented:
Yes, there is a limit, but it is much higher than that(From Confugiration Guide):

Chapter 10: Managing Adaptive Server Databases
Device requirements

The size and number of Adaptive Server devices depend on the following constraints:

    *       The maximum device size is 4TB.

    *      Each database can have up to 2G - 1devices.

    *      The maximum database size is 4 – 32 TB (dependent upon page size.)

Although some operating systems can designate an entire hard disk to use as a database device, Windows accepts only an operating system file (.dat file) as a database device.

When you install Adaptive Server, the program creates a .dat file in the \data directory of the Sybase installation directory. To use a .dat file as a database device, you can either use the default d:\sybase\data directory or create a device and a directory in which to store it.

0
 
Joe WoodhousePrincipal ConsultantCommented:
alpmoon has already given you the answer.

However note there are performance reasons to want to try to balance the size of devices with the number of devices.

It would be a bad idea to, say, create a 200Gb database on one 150Gb data device and one 50Gb log device. Each device is protected by a single semaphore, and if you make your devices too large, you'll get performance problems. (You can see this in sp_sysmon output, in the section on devices.)

Basically you should look at what the limiting factor is. If your operating system imposes a limit on raw partitions/LVOLs/LVMs/etc, then figure how large your database will ever grow to, double that number for headroom, and divide that by the maximum number of possible devices.

Let's say you think the database could never ever be larger than 2Tb. Then if we double that number to 4Tb, and divide by 250 LVMs, you get each device should be a bit over 16G each. Given you don't need all of those today, I'd stick with 16Gb devices for now, and you can make some 20Gb ones later if you start running out of room.

You can always resize devices, too - this would be a destructive rebuild where you tear down your system, put more storage in, recreate your Sybase devices and databases and reload from backup... but each device could now be larger.

Anyway. While you can have 150Gb devices, it is a bad idea. Unless you have truly large databases 16Gb will be plenty.
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.