在AIX下新建LV 4K偏移量问题-原创手记-慕课网

问题现象：

在AIX下新建LV，然后在LV上建表空间，出现WARNING（Oracle recommends creating new datafiles on devices with zero offset）

alter tablespace ZJ_DATA add datafile '/dev/rdata40_disk' size 2500M

Wed Apr 27 22:45:36 2011

WARNING: You are creating datafile /dev/rdata41_disk.

WARNING: Oracle recommends creating new datafiles on devices with zero offset. The command "/usr/sbin/mklv -y LVname -T O -w n -s n -r n VGname NumPPs" can be used. Please contact Oracle customer support for more details.

通过mklv -T O -y data40_disk oradatavg 1重建如上表空间后上述警告消失，运行一段时间数据库完全正常，可见数据文件已经正常写入该DATAFILE。

但无意中一次lslv对比了数据库上线时和刚刚建立的两个lv文件，发现在TYPE、DEVICESUBTYPE、RELOCATABLE、MIRROR WRITE CONSISTENCY、EACH LP COPY ON A SEPARATE PV

方面存在区别，详见如下。

$ lslv data40_disk

LOGICAL VOLUME: data40_disk VOLUME GROUP: oradatavg

LV IDENTIFIER: 00c164fe00004c0000000110a1021713.66 PERMISSION: read/write

VG STATE: active/complete LV STATE: opened/syncd

TYPE: jfs WRITE VERIFY: off

MAX LPs: 512 PP SIZE: 256 megabyte(s)

COPIES: 1 SCHED POLICY: parallel

LPs: 10 PPs: 10

STALE PPs: 0 BB POLICY: relocatable

INTER-POLICY: minimum RELOCATABLE: yes

INTRA-POLICY: middle UPPER BOUND: 16

MOUNT POINT: N/A LABEL: None

MIRROR WRITE CONSISTENCY: on/ACTIVE

EACH LP COPY ON A SEPARATE PV ?: yes

Serialize IO ?: NO

DEVICESUBTYPE : DS_LVZ

$ lslv data_disk

LOGICAL VOLUME: data_disk VOLUME GROUP: oradatavg

LV IDENTIFIER: 00c164fe00004c0000000110a1021713.14 PERMISSION: read/write

VG STATE: active/complete LV STATE: closed/syncd

TYPE: raw WRITE VERIFY: off

MAX LPs: 512 PP SIZE: 256 megabyte(s)

COPIES: 1 SCHED POLICY: parallel

LPs: 4 PPs: 4

STALE PPs: 0 BB POLICY: relocatable

INTER-POLICY: minimum RELOCATABLE: no

INTRA-POLICY: middle UPPER BOUND: 16

MOUNT POINT: N/A LABEL: None

MIRROR WRITE CONSISTENCY: off

EACH LP COPY ON A SEPARATE PV ?: no

Serialize IO ?: NO

为了鉴证MKLV命令的默认参数，我们来继续几个做测试

方法一：mklv带有 -T O参数，但是不指定TYPE(-t) ，新建的lv带DEVICESUBTYPE属性，且TYPE:jfs

p550a:/home/oracle/dba#mklv -T O -y data40_disk oradatavg 1

data40_disk

p550a:/home/oracle/dba#lslv data40_disk

LOGICAL VOLUME: data40_disk VOLUME GROUP: oradatavg

LV IDENTIFIER: 000037750000d60000000112749c9dbb.173 PERMISSION: read/write

VG STATE: active/complete LV STATE: closed/syncd

TYPE: jfs WRITE VERIFY: off

MAX LPs: 512 PP SIZE: 512 megabyte(s)

COPIES: 1 SCHED POLICY: parallel

LPs: 1 PPs: 1

STALE PPs: 0 BB POLICY: relocatable

INTER-POLICY: minimum RELOCATABLE: yes

INTRA-POLICY: middle UPPER BOUND: 32

MOUNT POINT: N/A LABEL: None

MIRROR WRITE CONSISTENCY: on/ACTIVE

EACH LP COPY ON A SEPARATE PV ?: yes

Serialize IO ?: NO

DEVICESUBTYPE : DS_LVZ

方法二：mklv带有 -T O参数，指定TYPE(-t 'raw') ，通过lslv可以看出，新建的lv带DEVICESUBTYPE属性，且TYPE:raw

p550a:/home/oracle/dba#mklv -T O -t 'raw' -y data41_disk oradatavg 1

data41_disk

p550a:/home/oracle/dba#lslv data41_disk

LOGICAL VOLUME: data41_disk VOLUME GROUP: oradatavg

LV IDENTIFIER: 000037750000d60000000112749c9dbb.174 PERMISSION: read/write

VG STATE: active/complete LV STATE: closed/syncd

TYPE: raw WRITE VERIFY: off

MAX LPs: 512 PP SIZE: 512 megabyte(s)

COPIES: 1 SCHED POLICY: parallel

LPs: 1 PPs: 1

STALE PPs: 0 BB POLICY: relocatable

INTER-POLICY: minimum RELOCATABLE: yes

INTRA-POLICY: middle UPPER BOUND: 32

MOUNT POINT: N/A LABEL: None

MIRROR WRITE CONSISTENCY: on/ACTIVE

EACH LP COPY ON A SEPARATE PV ?: yes

Serialize IO ?: NO

DEVICESUBTYPE : DS_LVZ

方法三：通过smitlv，指定TYPE(-t 'raw')建lv ，通过lslv可以看出，新建的lv不带DEVICESUBTYPE属性，且TYPE:raw

p550a:/home/oracle/dba#smit lv

添加逻辑卷

在输入字段中输入或选择值。

当完成所有希望的更改之后，按 Enter 键。

[输入字段]

逻辑卷名称 [data42_disk]

* 卷组名称 oradatavg

* 逻辑分区的数量 [1] #

物理卷名 [] +

逻辑卷类型 [raw] +

物理卷位置中间 +

物理卷范围最小 +

用于分配的 [] #

物理卷最大数量

每个逻辑分区的副本数量 1 +

要一致性镜像化写入吗? 主动 +

要将每个逻辑分区副本分配是 +

到一个单独的物理卷吗？

要在重新组织的过程中是 +

重新分配物理卷吗？

逻辑卷标号 []

逻辑分区的最大数量 [512] #

要启用坏块重定位吗？是 +

读取/写入的“规划策略” 并行 +

逻辑分区副本

要启用写入验证吗？否 +

包含分配映射的文件 []

组合分割区大小？ [未分割] +

序列化 IO？否

p550a:/home/oracle/dba#lslv data42_disk

LOGICAL VOLUME: data42_disk VOLUME GROUP: oradatavg

LV IDENTIFIER: 000037750000d60000000112749c9dbb.175 PERMISSION: read/write

VG STATE: active/complete LV STATE: closed/syncd

TYPE: raw WRITE VERIFY: off

MAX LPs: 512 PP SIZE: 512 megabyte(s)

COPIES: 1 SCHED POLICY: parallel

LPs: 1 PPs: 1

STALE PPs: 0 BB POLICY: relocatable

INTER-POLICY: minimum RELOCATABLE: yes

INTRA-POLICY: middle UPPER BOUND: 32

MOUNT POINT: N/A LABEL: None

MIRROR WRITE CONSISTENCY: on/ACTIVE

EACH LP COPY ON A SEPARATE PV ?: yes

Serialize IO ?: NO

方法四：mklv不带 -T O参数，但指定TYPE(-t 'raw') ，通过lslv可以看出，新建的lv不带DEVICESUBTYPE属性，且RELOCATABLE: yes

p550a:/#mklv -t 'raw' -y data43_disk oradatavg 1

data43_disk

p550a:/#lslv data43_disk

LOGICAL VOLUME: data43_disk VOLUME GROUP: oradatavg

LV IDENTIFIER: 000037750000d60000000112749c9dbb.176 PERMISSION: read/write

VG STATE: active/complete LV STATE: closed/syncd

TYPE: raw WRITE VERIFY: off

MAX LPs: 512 PP SIZE: 512 megabyte(s)

COPIES: 1 SCHED POLICY: parallel

LPs: 1 PPs: 1

STALE PPs: 0 BB POLICY: relocatable

INTER-POLICY: minimum RELOCATABLE: yes

INTRA-POLICY: middle UPPER BOUND: 32

MOUNT POINT: N/A LABEL: None

MIRROR WRITE CONSISTENCY: on/ACTIVE

EACH LP COPY ON A SEPARATE PV ?: yes

Serialize IO ?: NO

综合以上测试可以得出：

1、mklv默认的TYPE是jfs

2、默认建立普通类型的lv，LV类型是DS_LV，这种类型的LV，在lslv的命令中没有任何SUBTYPE类型说明（不带DEVICESUBTYPE : DS_LVZ）。

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