(2) Redo logs on F40 PCIe cards (non-volatile flash storage)

Per the F40 PCIe card user's guide, the Sun Flash Accelerator F40 PCIe Card is designed to provide best performance for data transfers that are multiples of 8k size, and using addresses that are 8k aligned. To achieve optimal performance, the size of the read/write data should be an integer multiple of this block size and the data transferred should be block aligned. I/O operations that are not block aligned and that do not use sizes that are a multiple of the block size may suffer performance degration, especially for write operations.

Oracle redo log files default to a block size that is equal to the physical sector size of the disk, typically 512 bytes. And most of the time, database writes to the redo log in a normal functioning environment. Oracle database supports a maximum block size of 4K for redo logs. Hence to achieve optimal performance for redo write operations on F40 PCIe cards, tune the environment as shown below.

1. Configure the following init parameters

   _disk_sector_size_override=TRUE
   _simulate_disk_sectorsize=4096
   

2. Create redo log files with 4K block size
   eg.,

   SQL> ALTER DATABASE ADD LOGFILE '/REDO/redo.dbf' size 20G blocksize 4096;
   

3. [Solaris only] Append the following line to /kernel/drv/sd.conf (requires a reboot)
   

   sd-config-list="ATA     3E128-TS2-550B01","disksort:false, cache-nonvolatile:true, physical-block-size:4096";
   

4. [Solaris only][F20] To enable maximum throughput from the MPT driver, append the following line to /kernel/drv/mpt.conf and reboot the system.

   mpt_doneq_thread_n_prop=8;
   

This tip is applicable to all kinds of flash storage that Oracle sells or sold including F20/F40 PCIe cards and F5100 storage array. sd-config-list in sd.conf may need some adjustment to reflect the correct vendor id and product id.