Kbase P142916: Can I stripe the database extents evenly across the same number of hard drives and put all of the ta
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
3/18/2009 |
|
Status: Unverified
GOAL:
Can I stripe the database extents evenly across the same number of hard drives and put all of the tables into the same Areas?
FACT(s) (Environment):
All Supported Operating Systems
Progress/OpenEdge Product Family
FIX:
Manually striping the data extents can work to even the disk workload but this method does have some limitations:
Compared to RAID disk striping,the granularity is much coarser and thus not as effective. With RAID disk striping, successive disk blocks go on successive drives, but with manual striping of database extents the unit of striping is whatever your extent size is. As the database grows you have to add new extents and keep them striped. The smaller you make the extents the more even the disk load will be, but using small extents means more open files. Connecting to the database and starting it up takes longer because more files have to be opened. You may run into the limit on open files per process or per system (which varies by operating system). If you have 100 extents and 100 self-service database connections, you will have a total of 10,000 open files or more (older versions of Progress will open some of the extents twice). On the plus side, more files means you may get better write concurrency because on some operating systems (or filesystems), only one write operation at a time can be performed to a given file. With more files, the probability of two simultaneous writes to the same file is reduced. If all the writes are performed by page writers then this is less of an issue.