Oracle ASM Virtually addressed metadata-Disk directory

Disk directory是asm的2号文件，对于磁盘组中的每一个磁盘都有对应的磁盘条目记录该asm磁盘的磁盘号，磁盘状态，磁盘名称，所在failgroup，创建时间，磁盘repair time等等信息，x$kfdsk部分信息来自于Disk directory。可以通过2号文件的File directory去定位Disk directory所在位置。

SQL> select PXN_KFFXP,DISK_KFFXP,AU_KFFXP from x$kffxp where GROUP_KFFXP=2 and NUMBER_KFFXP=2;

 PXN_KFFXP DISK_KFFXP   AU_KFFXP
---------- ---------- ----------
         0          2          2
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当asm磁盘组无法mount时，可以也通过kfed去读取2号文件的File directory，从而定位到Disk directory所在位置。

[grid@rac1 ~]$ kfed read /dev/asmdisk-data4|grep f1b1
kfdhdb.f1b1locn:                      2 ; 0x0d4: 0x00000002
[grid@rac1 ~]$ kfed read /dev/asmdisk-data4 aun=2 blkn=2|grep kfffde
kfffde[0].xptr.au:                    2 ; 0x4a0: 0x00000002
kfffde[0].xptr.disk:                  2 ; 0x4a4: 0x0002
kfffde[0].xptr.flags:                 0 ; 0x4a6: L=0 E=0 D=0 S=0
kfffde[0].xptr.chk:                  42 ; 0x4a7: 0x2a
kfffde[1].xptr.au:           4294967295 ; 0x4a8: 0xffffffff
kfffde[1].xptr.disk:              65535 ; 0x4ac: 0xffff
kfffde[1].xptr.flags:                 0 ; 0x4ae: L=0 E=0 D=0 S=0
kfffde[1].xptr.chk:                  42 ; 0x4af: 0x2a
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Disk directory最重要的结构就是磁盘条目(kfddde），其结构如下：

[grid@rac1 ~]$ kfed read /dev/asmdisk-data6 aun=2 |grep "kfddde\[0"|more
kfddde[0].entry.incarn:               1 ; 0x024: A=1 NUMM=0x0
kfddde[0].entry.hash:                 0 ; 0x028: 0x00000000
kfddde[0].entry.refer.number:4294967295 ; 0x02c: 0xffffffff
kfddde[0].entry.refer.incarn:         0 ; 0x030: A=0 NUMM=0x0
kfddde[0].dsknum:                     0 ; 0x034: 0x0000
kfddde[0].state:                      2 ; 0x036: KFDSTA_NORMAL
kfddde[0].ddchgfl:                  132 ; 0x037: 0x84
kfddde[0].dskname:         DATA_1M_0000 ; 0x038: length=12
kfddde[0].fgname:          DATA_1M_0000 ; 0x058: length=12
kfddde[0].crestmp.hi:          33115693 ; 0x078: HOUR=0xd DAYS=0x11 MNTH=0x3 YEAR=0x7e5
kfddde[0].crestmp.lo:        2729510912 ; 0x07c: USEC=0x0 MSEC=0x42 SECS=0x2b MINS=0x28
kfddde[0].failstmp.hi:                0 ; 0x080: HOUR=0x0 DAYS=0x0 MNTH=0x0 YEAR=0x0
kfddde[0].failstmp.lo:                0 ; 0x084: USEC=0x0 MSEC=0x0 SECS=0x0 MINS=0x0
kfddde[0].timer:                      0 ; 0x088: 0x00000000
kfddde[0].size:                    5120 ; 0x08c: 0x00001400
kfddde[0].srRloc.super.hiStart:       0 ; 0x090: 0x00000000
kfddde[0].srRloc.super.loStart:       0 ; 0x094: 0x00000000
kfddde[0].srRloc.super.length:        0 ; 0x098: 0x00000000
kfddde[0].srRloc.incarn:              0 ; 0x09c: 0x00000000
kfddde[0].dskrprtm:                   0 ; 0x0a0: 0x00000000
kfddde[0].start0:                     0 ; 0x0a4: 0x00000000
kfddde[0].size0:                   5120 ; 0x0a8: 0x00001400
kfddde[0].used0:                     22 ; 0x0ac: 0x00000016
kfddde[0].slot:                       0 ; 0x0b0: 0x00000000
kfddde[0].imbal00[0]:                20 ; 0x0b4: 0x00000014

The disk directory structure (kfddde) is defined as follows:
KF3_FIELD(kfddde, kffden, entry_kfddde)               /* Common entry fields */
KF3_FIELD(kfddde, ub2, dsknum_kfddde)                 /* Disk number [KEY] */
KF3_FIELD(kfddde, kfdsta, state_kfddde)               /* Disk state */
KF3_FIELD(kfddde, kfddchfl, ddchgfl_kfddde)           /* Bit flags for chngs */
KF3_ARRAY(kfddde, oratext, KFD_IDENT, dskname_kfddde) /* ASM disk name */
KF3_ARRAY(kfddde, oratext, KFD_IDENT, fgname_kfddde)  /* Fail group name */
KF3_FIELD(kfddde, kfts, crestmp_kfddde)               /* Create timestamp */
KF3_FIELD(kfddde, kfts, failstmp_kfddde)              /* Failure timestamp */
KF3_FIELD(kfddde, ub4, timer_kfddde)                  /* Failure timer */
KF3_FIELD(kfddde, ub4, size_kfddde)                   /* Resize target(AUs) */
KF3_FIELD(kfddde, kfdsDdLoc, srRloc_kfddde)           /* Relative loc in SR */
KF3_FIELD(kfddde, ub4, dskrprtm_kfddde)               /* Disk repair time */
KF3_ARRAY(kfddde, kfdzon, KFDZN_LAST, zones_kfddde)   /* Zone information */
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• dsknum：磁盘号
• dskname：磁盘组名
• fgname：failgroup名
• crestmp：创建时间(hi为高位，lo为低位)
• dskrprtm：repair time
• state：磁盘状态

#define KFDSTA_INVALID ((kfdsta)0) /* Illegal value */
#define KFDSTA_UNKNOWN ((kfdsta)1) /* ASM disk state not known */
#define KFDSTA_NORMAL ((kfdsta)2) /* Happy disk */
#define KFDSTA_UNUSED ((kfdsta)3) /* Unused State - Open */
#define KFDSTA_DROPPING ((kfdsta)4) /* Disk being dropped from group */
#define KFDSTA_HUNG ((kfdsta)5) /* Disk drop operation hung */
#define KFDSTA_FORCING ((kfdsta)6) /* Disk beinng drop forced */
#define KFDSTA_DROPPED ((kfdsta)7) /* Disk no longer part of group */
#define KFDSTA_ADDING ((kfdsta)8) /* Disk being globally validated */
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• ddchgfl：标志位

kf3.h:#define KFDDCHFL_FLGUNST ((kfddchfl)0x00) /* Nothing set */
kf3.h:#define KFDDCHFL_RPRTMST ((kfddchfl)0x01) /* dskrprtm_kfddde set*/
kf3.h:#define KFDDCHFL_OFLTMST ((kfddchfl)0x02) /* timer_kfddde set */
kf3.h:#define KFDDCHFL_ASMCV11 ((kfddchfl)0x80) /* ASM compat lvl v11 */
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