Partnership and Status Table(PST)包含了关于磁盘组中所有ASM磁盘的信息，比如，磁盘号，磁盘状态，伙伴磁盘号，心跳信息与故障磁盘组信息(11g及以后版本)。PST跟踪磁盘组的成员关系与磁盘的伙伴关系。ASM为了在mount磁盘组时来判断是否有足够的一组磁盘被online就会咨询PST。每个ASM磁盘中的AU 1被保留给PST使用，但只有某些磁盘有PST数据。
PST count
在任何时候，磁盘组有受限数量的活动PSTs。PSTs的数量是由磁盘组的冗余类型与故障磁盘组数量所决定的。对于外部冗余磁盘组它只有一个PST副本。对于正常冗余磁盘组至少有两个PST副本。如果存在三个或多个故障磁盘组，它将有三个PST副本。对于高冗余磁盘组至少有三个PST副本。如果存在四个故障磁盘组，它将有四个PST副本，并且如果有五个或多个故障磁盘组，它将有五个PST副本。
下面通过例子来说明每种冗余磁盘组所包含的PST数量
1.外部冗余磁盘组
SQL> create diskgroup testdg external redundancy disk '/dev/raw/raw5','/dev/raw/raw6','/dev/raw/raw7','/dev/raw/raw12','/dev/raw/raw13','/dev/raw/raw14'; Diskgroup created.
ASM alert log信息如下:
SQL> create diskgroup testdg external redundancy disk '/dev/raw/raw5','/dev/raw/raw6','/dev/raw/raw7','/dev/raw/raw12','/dev/raw/raw13','/dev/raw/raw14' NOTE: Assigning number (4,0) to disk (/dev/raw/raw5) NOTE: Assigning number (4,1) to disk (/dev/raw/raw6) NOTE: Assigning number (4,2) to disk (/dev/raw/raw7) NOTE: Assigning number (4,3) to disk (/dev/raw/raw12) NOTE: Assigning number (4,4) to disk (/dev/raw/raw13) NOTE: Assigning number (4,5) to disk (/dev/raw/raw14) NOTE: initializing header on grp 4 disk TESTDG_0000 NOTE: initializing header on grp 4 disk TESTDG_0001 NOTE: initializing header on grp 4 disk TESTDG_0002 NOTE: initializing header on grp 4 disk TESTDG_0003 NOTE: initializing header on grp 4 disk TESTDG_0004 NOTE: initializing header on grp 4 disk TESTDG_0005 NOTE: initiating PST update: grp = 4 Thu Dec 22 08:51:03 2016 GMON updating group 4 at 16 for pid 30, osid 6861 NOTE: group TESTDG: initial PST location: disk 0000 (PST copy 0) NOTE: PST update grp = 4 completed successfully
从上面的信息可以看到只有一个PST副本
2.正常冗余磁盘组
SQL> create diskgroup testdg normal redundancy disk '/dev/raw/raw5','/dev/raw/raw6','/dev/raw/raw7','/dev/raw/raw12','/dev/raw/raw13','/dev/raw/raw14'; Diskgroup created.
ASM alert log信息如下:
SQL> create diskgroup testdg normal redundancy disk '/dev/raw/raw5','/dev/raw/raw6','/dev/raw/raw7','/dev/raw/raw12','/dev/raw/raw13','/dev/raw/raw14' NOTE: Assigning number (4,0) to disk (/dev/raw/raw5) NOTE: Assigning number (4,1) to disk (/dev/raw/raw6) NOTE: Assigning number (4,2) to disk (/dev/raw/raw7) NOTE: Assigning number (4,3) to disk (/dev/raw/raw12) NOTE: Assigning number (4,4) to disk (/dev/raw/raw13) NOTE: Assigning number (4,5) to disk (/dev/raw/raw14) NOTE: initializing header on grp 4 disk TESTDG_0000 NOTE: initializing header on grp 4 disk TESTDG_0001 NOTE: initializing header on grp 4 disk TESTDG_0002 NOTE: initializing header on grp 4 disk TESTDG_0003 NOTE: initializing header on grp 4 disk TESTDG_0004 NOTE: initializing header on grp 4 disk TESTDG_0005 Fri Dec 23 08:05:45 2016 GMON updating for reconfiguration, group 4 at 24 for pid 30, osid 6861 NOTE: group 4 PST updated. NOTE: initiating PST update: grp = 4 GMON updating group 4 at 25 for pid 30, osid 6861 NOTE: group TESTDG: initial PST location: disk 0000 (PST copy 0) NOTE: group TESTDG: initial PST location: disk 0001 (PST copy 1) NOTE: group TESTDG: initial PST location: disk 0002 (PST copy 2) NOTE: PST update grp = 4 completed successfully
从上面的信息可以看到有三个PST副本
3.高冗余磁盘组
SQL> create diskgroup testdg high redundancy disk '/dev/raw/raw5','/dev/raw/raw6','/dev/raw/raw7','/dev/raw/raw12','/dev/raw/raw13','/dev/raw/raw14'; Diskgroup created.
ASM alert log信息如下:
SQL> create diskgroup testdg high redundancy disk '/dev/raw/raw5','/dev/raw/raw6','/dev/raw/raw7','/dev/raw/raw12','/dev/raw/raw13','/dev/raw/raw14' NOTE: Assigning number (4,0) to disk (/dev/raw/raw5) NOTE: Assigning number (4,1) to disk (/dev/raw/raw6) NOTE: Assigning number (4,2) to disk (/dev/raw/raw7) NOTE: Assigning number (4,3) to disk (/dev/raw/raw12) NOTE: Assigning number (4,4) to disk (/dev/raw/raw13) NOTE: Assigning number (4,5) to disk (/dev/raw/raw14) NOTE: initializing header on grp 4 disk TESTDG_0000 NOTE: initializing header on grp 4 disk TESTDG_0001 NOTE: initializing header on grp 4 disk TESTDG_0002 NOTE: initializing header on grp 4 disk TESTDG_0003 NOTE: initializing header on grp 4 disk TESTDG_0004 NOTE: initializing header on grp 4 disk TESTDG_0005 Fri Dec 23 08:18:04 2016 GMON updating for reconfiguration, group 4 at 33 for pid 30, osid 6861 NOTE: group 4 PST updated. NOTE: initiating PST update: grp = 4 GMON updating group 4 at 34 for pid 30, osid 6861 NOTE: group TESTDG: initial PST location: disk 0000 (PST copy 0) NOTE: group TESTDG: initial PST location: disk 0001 (PST copy 1) NOTE: group TESTDG: initial PST location: disk 0002 (PST copy 2) NOTE: group TESTDG: initial PST location: disk 0003 (PST copy 3) NOTE: group TESTDG: initial PST location: disk 0004 (PST copy 4) NOTE: PST update grp = 4 completed successfully
从上面的信息可以看到有五个PST副本
PST重新定位
在以下情况下PST将会重新定位:
.(在ASM启动时)磁盘的PST不可用
.磁盘脱机
.当对PST执行读/写时出现I/O错误
.磁盘被删除
对于以上情况PST将会被重新定位到相同故障磁盘组的另一个磁盘上(相同故障磁盘组中可用的磁盘上）或另一个故障磁盘组中的磁盘上(哪些不包括PST副本的磁盘）。
例如:
SQL> drop diskgroup testdg; Diskgroup dropped. SQL> create diskgroup testdg normal redundancy disk '/dev/raw/raw5','/dev/raw/raw6','/dev/raw/raw7','/dev/raw/raw12','/dev/raw/raw13','/dev/raw/raw14'; Diskgroup created.
ASM alert log信息显示PST副本分布存储在disk 0,1和2:
NOTE: group TESTDG: initial PST location: disk 0000 (PST copy 0) NOTE: group TESTDG: initial PST location: disk 0001 (PST copy 1) NOTE: group TESTDG: initial PST location: disk 0002 (PST copy 2) 我们现在来删除disk 0:
SQL> select disk_number, name, path from v$asm_disk_stat where group_number = (select group_number from v$asm_diskgroup_stat where name='TESTDG') order by disk_number asc;
DISK_NUMBER NAME PATH
----------- ------------------------------ ------------------------------
0 TESTDG_0000 /dev/raw/raw5
1 TESTDG_0001 /dev/raw/raw6
2 TESTDG_0002 /dev/raw/raw7
3 TESTDG_0003 /dev/raw/raw12
4 TESTDG_0004 /dev/raw/raw13
5 TESTDG_0005 /dev/raw/raw14
6 rows selected.
SQL> alter diskgroup testdg drop disk TESTDG_0000;
Diskgroup altered.
ASM alert log信息
SQL> alter diskgroup testdg drop disk TESTDG_0000 NOTE: GroupBlock outside rolling migration privileged region NOTE: requesting all-instance membership refresh for group=4 Fri Dec 23 09:05:37 2016 GMON updating for reconfiguration, group 4 at 50 for pid 30, osid 6861 NOTE: group 4 PST updated. Fri Dec 23 09:05:38 2016 NOTE: membership refresh pending for group 4/0xce186197 (TESTDG) GMON querying group 4 at 51 for pid 18, osid 5012 SUCCESS: refreshed membership for 4/0xce186197 (TESTDG) NOTE: starting rebalance of group 4/0xce186197 (TESTDG) at power 1 SUCCESS: alter diskgroup testdg drop disk TESTDG_0000 Starting background process ARB0 Fri Dec 23 09:05:41 2016 ARB0 started with pid=36, OS id=23811 NOTE: assigning ARB0 to group 4/0xce186197 (TESTDG) with 1 parallel I/O cellip.ora not found. NOTE: F1X0 copy 1 relocating from 0:2 to 4:28 for diskgroup 4 (TESTDG) Fri Dec 23 09:05:53 2016 NOTE: stopping process ARB0 SUCCESS: rebalance completed for group 4/0xce186197 (TESTDG) NOTE: Attempting voting file refresh on diskgroup TESTDG NOTE: Refresh completed on diskgroup TESTDG. No voting file found. Fri Dec 23 09:05:53 2016 NOTE: GroupBlock outside rolling migration privileged region NOTE: requesting all-instance membership refresh for group=4 Fri Dec 23 09:05:56 2016 GMON updating for reconfiguration, group 4 at 52 for pid 36, osid 23854 NOTE: group 4 PST updated. SUCCESS: grp 4 disk TESTDG_0000 emptied NOTE: erasing header on grp 4 disk TESTDG_0000 NOTE: process _x000_+asm1 (23854) initiating offline of disk 0.3915944465 (TESTDG_0000) with mask 0x7e in group 4 NOTE: initiating PST update: grp = 4, dsk = 0/0xe9689211, mask = 0x6a, op = clear GMON updating disk modes for group 4 at 53 for pid 36, osid 23854 NOTE: group TESTDG: updated PST location: disk 0001 (PST copy 0) NOTE: group TESTDG: updated PST location: disk 0002 (PST copy 1) NOTE: group TESTDG: updated PST location: disk 0003 (PST copy 2)
我们现在来删除disk 0:
SQL> select disk_number, name, path from v$asm_disk_stat where group_number = (select group_number from v$asm_diskgroup_stat where name='TESTDG') order by disk_number asc;
DISK_NUMBER NAME PATH
----------- ------------------------------ ------------------------------
0 TESTDG_0000 /dev/raw/raw5
1 TESTDG_0001 /dev/raw/raw6
2 TESTDG_0002 /dev/raw/raw7
3 TESTDG_0003 /dev/raw/raw12
4 TESTDG_0004 /dev/raw/raw13
5 TESTDG_0005 /dev/raw/raw14
6 rows selected.
PST可用性
PST表的数据要先于其他ASM元数据之前可用。当磁盘组被请求mount时，GMON进程(在ASM实例请求mount)会读取磁盘组中的所有磁盘来找到并验证所有可用的PST副本。一旦它验证有足够的PST，就会mount磁盘组。从这个时刻开始，PST表的信息储存在ASM实例的cache里；位于GMON 进程的PGA中，由PT.n.0 enqueue排他锁进行保护。对于同一集群的其他ASM实例，在启动之后会把PST表缓存在自己的GMON PGA中，加上共享的PT.n.0 enqueue。只有拥有排他PT enqueue锁的GMON进程（10gR1中为CKPT），可以更新磁盘中的PST表信息。
PST(GMON)跟踪
每次尝试mount磁盘组时，GMON trace文件就会记录PST信息。注意我说的是尝试，不是已经mount上。换句话说，GMON不管mount动作成功与否，都会记录信息。这些信息对于Oracle Support诊断磁盘组mount失败故障可能会有价值。
下面查看GMON trace文件记录的testdg磁盘组mount的信息：
[grid@jyrac1 trace]$ ls -lrt *gmon* -rw-r----- 1 grid oinstall 276 Nov 22 18:25 +ASM1_gmon_21379.trm -rw-r----- 1 grid oinstall 9953 Nov 22 18:25 +ASM1_gmon_21379.trc -rw-r----- 1 grid oinstall 631 Nov 23 07:57 +ASM1_gmon_22366.trm -rw-r----- 1 grid oinstall 26275 Nov 23 07:57 +ASM1_gmon_22366.trc -rw-r----- 1 grid oinstall 809 Nov 24 09:01 +ASM1_gmon_4906.trm -rw-r----- 1 grid oinstall 41769 Nov 24 09:01 +ASM1_gmon_4906.trc -rw-r----- 1 grid oinstall 263 Nov 24 09:06 +ASM1_gmon_18658.trm -rw-r----- 1 grid oinstall 17305 Nov 24 09:06 +ASM1_gmon_18658.trc -rw-r----- 1 grid oinstall 256 Nov 24 09:12 +ASM1_gmon_20072.trm -rw-r----- 1 grid oinstall 17274 Nov 24 09:12 +ASM1_gmon_20072.trc -rw-r----- 1 grid oinstall 263 Nov 24 09:14 +ASM1_gmon_20707.trm -rw-r----- 1 grid oinstall 17300 Nov 24 09:14 +ASM1_gmon_20707.trc -rw-r----- 1 grid oinstall 332 Nov 24 09:26 +ASM1_gmon_22827.trm -rw-r----- 1 grid oinstall 17595 Nov 24 09:26 +ASM1_gmon_22827.trc -rw-r----- 1 grid oinstall 262 Nov 24 09:48 +ASM1_gmon_26737.trm -rw-r----- 1 grid oinstall 15829 Nov 24 09:48 +ASM1_gmon_26737.trc -rw-r----- 1 grid oinstall 2175 Dec 14 16:57 +ASM1_gmon_4909.trm -rw-r----- 1 grid oinstall 178545 Dec 14 16:57 +ASM1_gmon_4909.trc -rw-r----- 1 grid oinstall 1616 Dec 23 09:05 +ASM1_gmon_5014.trm -rw-r----- 1 grid oinstall 135047 Dec 23 09:05 +ASM1_gmon_5014.trc
[grid@jyrac1 trace]$ cat +ASM1_gmon_5014.trc *** 2016-12-23 09:05:56.534 GMON updating disk modes for group 4 at 53 for pid 36, osid 23854 dsk = 0/0xe9689211, mask = 0x6a, op = clear PRE =============== PST ==================== grpNum: 4 state: 1 callCnt: 53 (lockvalue) valid=1 ver=1.1 ndisks=3 flags=0x0 from inst=1 (I am 1) last=4 (lockvalue) dsks: 0 1 2 --------------- HDR -------------------- next: 4 last: 4 pst count: 3 pst locations: 0 1 2 incarn: 1 dta size: 6 version: 0 ASM version: 168820736 = 10.1.0.0.0 contenttype: 0 partnering pattern: [ ] --------------- LOC MAP ---------------- 0: dirty 0 cur_loc: 0 stable_loc: 0 1: dirty 0 cur_loc: 1 stable_loc: 1 --------------- DTA -------------------- 0: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 1: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 2 (amp) 3 (amp) 4 (amp) 5 (amp) 2: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 1 (amp) 3 (amp) 4 (amp) 5 (amp) 3: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 1 (amp) 2 (amp) 4 (amp) 5 (amp) 4: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 1 (amp) 2 (amp) 3 (amp) 5 (amp) 5: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 1 (amp) 2 (amp) 3 (amp) 4 (amp)
=== PST ===标记的部分显示了磁盘组号（grpNum）,状态，例如grpNum: 4 说明磁盘组号为4，就是testdg磁盘组
SQL> select group_number,name,block_size,allocation_unit_size,state,type from v$asm_diskgroup where group_number=4;
GROUP_NUMBER NAME BLOCK_SIZE ALLOCATION_UNIT_SIZE STATE TYPE
------------ ------------------------------ ---------- -------------------- ---------------------- ------------
4 TESTDG 4096 1048576 MOUNTED NORMAL
— HDR —标记的部分显示了PST的副本数（pst count）和所在的磁盘号，例如这里显示了有3个PST,分别存储在disk
0000,0001,0002 pst count: 3 pst locations: 0 1 2
— DTA —显示了PST所在磁盘的状态
0: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 1: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 2 (amp) 3 (amp) 4 (amp) 5 (amp) 2: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 1 (amp) 3 (amp) 4 (amp) 5 (amp) 3: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 1 (amp) 2 (amp) 4 (amp) 5 (amp) 4: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 1 (amp) 2 (amp) 3 (amp) 5 (amp) 5: sts v v(rw) p(rw) a(x) d(x) fg# = 0 addTs = 0 parts: 1 (amp) 2 (amp) 3 (amp) 4 (amp)
可以看到PST副本所在磁盘从原来的disk 0000,disk 0001,disk 0002变成了现在的disk 0001,disk 0002,disk 0003了。我们也可以使用kfed来验证PST只存在于testdg磁盘组中的disk 0001,disk 0002,disk 0003的三块磁盘上
SQL> select disk_number, name, path from v$asm_disk_stat where group_number = (select group_number from v$asm_diskgroup_stat where name='TESTDG') order by disk_number asc;
DISK_NUMBER NAME PATH
----------- ------------------------------ ------------------------------
1 TESTDG_0001 /dev/raw/raw6
2 TESTDG_0002 /dev/raw/raw7
3 TESTDG_0003 /dev/raw/raw12
4 TESTDG_0004 /dev/raw/raw13
5 TESTDG_0005 /dev/raw/raw14
testdg中的disk 0001,0002,0003对应的磁盘就是/dev/raw/raw6,7,12:
[grid@jyrac1 trace]$ kfed read /dev/raw/raw6 aun=1 blkn=0 | grep type kfbh.type: 17 ; 0x002: KFBTYP_PST_META [grid@jyrac1 trace]$ kfed read /dev/raw/raw6 aun=1 blkn=1 | grep type kfbh.type: 17 ; 0x002: KFBTYP_PST_META [grid@jyrac1 trace]$ kfed read /dev/raw/raw6 aun=1 blkn=2 | grep type kfbh.type: 18 ; 0x002: KFBTYP_PST_DTA [grid@jyrac1 trace]$ kfed read /dev/raw/raw6 aun=1 blkn=3 | grep type kfbh.type: 18 ; 0x002: KFBTYP_PST_DTA [grid@jyrac1 trace]$ kfed read /dev/raw/raw6 aun=1 blkn=4 | grep type kfbh.type: 13 ; 0x002: KFBTYP_PST_NONE
从上面的信息可以看到在磁盘的au 1都是用来存储PST。其中块(块号从0开始)1,2用来存储的PST元数据，块3,4用来存储的PST数据，还可以看到块5没有存储任何数据，下面的磁盘/dev/raw/raw7,12的情况与/dev/raw/raw6是一样的
[grid@jyrac1 trace]$ kfed read /dev/raw/raw7 aun=1 blkn=0 | grep type kfbh.type: 17 ; 0x002: KFBTYP_PST_META [grid@jyrac1 trace]$ kfed read /dev/raw/raw7 aun=1 blkn=1 | grep type kfbh.type: 17 ; 0x002: KFBTYP_PST_META [grid@jyrac1 trace]$ kfed read /dev/raw/raw7 aun=1 blkn=2 | grep type kfbh.type: 18 ; 0x002: KFBTYP_PST_DTA [grid@jyrac1 trace]$ kfed read /dev/raw/raw7 aun=1 blkn=3 | grep type kfbh.type: 18 ; 0x002: KFBTYP_PST_DTA [grid@jyrac1 trace]$ kfed read /dev/raw/raw7 aun=1 blkn=4 | grep type kfbh.type: 13 ; 0x002: KFBTYP_PST_NONE [grid@jyrac1 trace]$ kfed read /dev/raw/raw12 aun=1 blkn=0 | grep type kfbh.type: 17 ; 0x002: KFBTYP_PST_META [grid@jyrac1 trace]$ kfed read /dev/raw/raw12 aun=1 blkn=1 | grep type kfbh.type: 17 ; 0x002: KFBTYP_PST_META [grid@jyrac1 trace]$ kfed read /dev/raw/raw12 aun=1 blkn=2 | grep type kfbh.type: 18 ; 0x002: KFBTYP_PST_DTA [grid@jyrac1 trace]$ kfed read /dev/raw/raw12 aun=1 blkn=3 | grep type kfbh.type: 18 ; 0x002: KFBTYP_PST_DTA [grid@jyrac1 trace]$ kfed read /dev/raw/raw12 aun=1 blkn=4 | grep type kfbh.type: 13 ; 0x002: KFBTYP_PST_NONE
从下面的信息可以看到disk 0004,0005对应的/dev/raw/raw13,14的AU 1中没有存储PST相关数据。
[grid@jyrac1 trace]$ kfed read /dev/raw/raw13 aun=1 blkn=0 | grep type kfbh.type: 13 ; 0x002: KFBTYP_PST_NONE [grid@jyrac1 trace]$ kfed read /dev/raw/raw14 aun=1 blkn=0 | grep type kfbh.type: 13 ; 0x002: KFBTYP_PST_NONE
查看PST元数据
[grid@jyrac1 trace]$ kfed read /dev/raw/raw6 aun=1 blkn=0 | more kfbh.endian: 1 ; 0x000: 0x01 --0 表示big endian,1 表示little endian. kfbh.hard: 130 ; 0x001: 0x82 --表示HARD magic number kfbh.type: 17 ; 0x002: KFBTYP_PST_META --表示PST元数据块 kfbh.datfmt: 1 ; 0x003: 0x01 --表示元数据块格式 kfbh.block.blk: 256 ; 0x004: blk=256 --表示块号，那为什么这里是256，因为AU的大小是1M,块大小是4K,一个AU包含256个块，而块号是从0开始，第一个AU(AU 0)的最大块号就是255,那么第二个AU(AU 1)的第一个块的块号就是256 kfbh.block.obj: 2147483649 ; 0x008: disk=1 kfbh.check: 2539674092 ; 0x00c: 0x976059ec --做校验用的，check一致性 kfbh.fcn.base: 0 ; 0x010: 0x00000000 kfbh.fcn.wrap: 0 ; 0x014: 0x00000000 kfbh.spare1: 0 ; 0x018: 0x00000000 kfbh.spare2: 0 ; 0x01c: 0x00000000 kfdpHdrBv0.time.hi: 33043177 ; 0x000: HOUR=0x9 DAYS=0x17 MNTH=0xc YEAR=0x7e0 --最后一次pst元数据的更新时间，精确到小时 kfdpHdrBv0.time.lo: 395175936 ; 0x004: USEC=0x0 MSEC=0x37a SECS=0x38 MINS=0x5 --最后一次pst元数据的更新时间，精确到微秒 kfdpHdrBv0.last: 7 ; 0x008: 0x00000007 --最新的disk版本号 kfdpHdrBv0.next: 7 ; 0x00c: 0x00000007 --下一个disk版本号 kfdpHdrBv0.copyCnt: 3 ; 0x010: 0x03 --表示PST元数据的备份信息，3表示磁盘组是normal冗余。1表示磁盘组是external冗余。 kfdpHdrBv0.version: 0 ; 0x011: 0x00 kfdpHdrBv0.ub2spare: 0 ; 0x012: 0x0000 kfdpHdrBv0.incarn: 4 ; 0x014: 0x00000004 kfdpHdrBv0.copy[0]: 1 ; 0x018: 0x0001 kfdpHdrBv0.copy[1]: 2 ; 0x01a: 0x0002 kfdpHdrBv0.copy[2]: 3 ; 0x01c: 0x0003 kfdpHdrBv0.copy[3]: 0 ; 0x01e: 0x0000 kfdpHdrBv0.copy[4]: 0 ; 0x020: 0x0000 kfdpHdrBv0.dtaSz: 6 ; 0x022: 0x0006 --表示pst元数据中，diskgroup所包含的disk个数 ub1[0]: 0 ; 0x024: 0x00 ub1[1]: 0 ; 0x025: 0x00 ub1[2]: 0 ; 0x026: 0x00 ub1[3]: 0 ; 0x027: 0x00 ub1[4]: 0 ; 0x028: 0x00 ub1[5]: 0 ; 0x029: 0x00 ub1[6]: 0 ; 0x02a: 0x00 ub1[7]: 0 ; 0x02b: 0x00 ub1[8]: 0 ; 0x02c: 0x00 ub1[9]: 0 ; 0x02d: 0x00 ub1[10]: 0 ; 0x02e: 0x00 ub1[11]: 0 ; 0x02f: 0x00 ub1[12]: 0 ; 0x030: 0x00 ub1[13]: 0 ; 0x031: 0x00 ub1[14]: 0 ; 0x032: 0x00 ub1[15]: 0 ; 0x033: 0x00 ub1[16]: 0 ; 0x034: 0x00 ub1[17]: 0 ; 0x035: 0x00 ub1[18]: 0 ; 0x036: 0x00
磁盘伙伴
磁盘的Partnership是在normal或者high冗余的磁盘组上，在两个磁盘之间有一个“对称”的关系。在external冗余中，不存在disk partnership。
小结
PST（Partnership and Status Table）包含一个磁盘组里所有磁盘的相关信息 — 磁盘号，磁盘状态，partner磁盘号，心跳信息和failgroup信息（11g之后）。每个ASM磁盘的第二AU(AU 1)被保留给PST使用，但是只有部分磁盘有PST数据。由于PST是重要的ASM元数据，只要故障磁盘组个数足够，在normal冗余中将会有三副本，在high冗余中将会有五副本。