LV's with VG's distriburion

[Ahmed_58]

Hi,
With new VG's and LV's for Oracle Filesystems. what is the best way is for good preformance.

Rgds,
Ahmed

[Devender Khatana]

Hi,

Importantly what hardware are you going to use to create these LVOLs and VGs?

What is the protection you are adopting i.e. mirroring etc. is it at hardware level or at LVOL level only.

These are important factors to be considered in deciding the parameters and layout.

HTH,
Devender

[Sandman!]

Just a few high-level rules of thumb that might help in optimizing your Oracle application:

- Stripe the data for parallelizing I/O to disks.
- Consider using raw vols alongwith asynchronous I/O.
- Monitor and tweak the buffer cache for optimal performance.
- Use HP Online JFS and tune its mount options mincache, and convosync and defragment extents periodically using fsadm.
- Look into Oracle documentation for tuning DML and DDL statements using hints for the optimizer, avoiding full table scans and efficiently allocating and using the SGA.

cheers!

[Senthil Kumar .A_1 · Accepted solution]

Hi,

firstly, If the PV's for the VG are created from Disk arrays, ex: XP, EVA,Hitachi USP of EMC storages, you would already have High availabilty and disk protection at hardware itself. In that case, Since Oracle app may quite often use sequencial writes, I would think about creating a LV with "block striping" there by gaining lot in performance. I wouldn't bother about redundancy using mirroring software much at the LVM level because, I have the protection at H/W level itself using Hardware Raids.

secondly, If PV's are standalone scsi disks connected to system. There are 2 situations with some trade-off's..

1) If my prime concern is data protection of the oracle Data and least downtime, then I would simply forget about striping, and just create a LV with its extents mirrored for data protection.

Though the Striping is possible with mirror co-existence, I will have to stick on with Extent striping(distribution), and basical I would not get a big performance gain. So its not worth to implement RAID 1/0

2) If my prime concern is just performance. Then I simply create a "block stripped" LV. And for data protection I will stick to the basic tools like, backing up, where by ,though I can recover data, the tradeoff is for longer recovery time.

Regards,
Senthil Kumar .A

[Ahmed_58]

thanks all for your usful advice.
Regards,
Ahmed