对4k sector size的一点认识

对4k sector size的一点认识:
1. 只有asmlib包才支持4k的sector size,也就是说---udev方式的asm diskgroup 不支持4k的sector size

     asmlib包的新特性: ORACLEASM_USE_LOGICAL_BLOCK_SIZE

     该特性适用的asmlib版本和UEK内核版本:This new feature is available in oracleasm-support-2.1.8-1 and kernel-uek 2.6.39-400.4.0 or later.

     New Block Size Feature for OracleASM and oracleasm-support (文档 ID 1530578.1)

2. GI 11.2.0.4(不打GI的PSU),在v$asm_diskgroup中,显示不了4k大小的asm diskgroup,这是GI的bug.

   详见文档Bug 18799063 - PGA memory corruption / errors with ASM on disks with blocksize > 512 bytes (文档 ID 18799063.8)

3. 检查disk 的block size的方法:

[root@node1 ~]# grep "" /sys/block/*/queue/*block_size
/sys/block/nvme0n1/queue/logical_block_size:512
/sys/block/nvme0n1/queue/physical_block_size:512
/sys/block/sda/queue/logical_block_size:512
/sys/block/sda/queue/physical_block_size:512
/sys/block/sdb/queue/logical_block_size:512
/sys/block/sdb/queue/physical_block_size:4096
[root@node1 ~]# 

参考文章:

Using 4k Redo Logs on Flash and SSD-based Storage (文档 ID 1681266.1)

Supporting ASM on 4K/4096 Sector Size (SECTOR_SIZE) Disks (文档 ID 1630790.1)--------->>>请仔细阅读该文章提到的pdf.

CRS Not Able to Discover Voting Disk after Kernel and Module kmod-oracleasm Upgrade (文档 ID 1994371.1)---->>值得一读

http://mt.sohu.com/20160405/n443331874.shtml

http://blog.csdn.net/msdnchina/article/details/51697272