linux lvm+raw设备 表空间可用空间测试

本文主要验证lvm+raw设备 表空间的最大可用空间大小

--1.建表空间之前的准备,/dev/raw/raw14大小为8M
[oracle@master ~]$  ln -s /dev/raw/raw14 /oracle/oradata/rawt/test01.dbf

--2.创建表空间
SQL> create tablespace test
datafile '/oracle/oradata/rawt/test01.dbf' size 2M
 autoextend on;

--3.查看文件大小，并插入数据直到空间不足
SQL> select bytes/1024/1024,maxbytes/1024/1024 from dba_data_files where file_id=5;

BYTES/1024/1024 MAXBYTES/1024/1024
--------------- ------------------
              2         32767.9844       --创建表空间时，没有指定最大值，这个地方为约32G

SQL>
SQL>
SQL>
SQL>
SQL> select count(*) from  dba_objects;

  COUNT(*)
----------
     50032

SQL> create table t (id int,name varchar2(20)) tablespace test;

Table created.

SQL>  insert into t select rownum,'1111111111' from dba_objects where rownum<50000;

49999 rows created.

SQL> commit;

Commit complete.

SQL>  insert into t select rownum,'1111111111' from dba_objects where rownum<50000;

49999 rows created.

SQL> commit;

Commit complete.

SQL>  insert into t select rownum,'1111111111' from dba_objects where rownum<50000;

49999 rows created.

SQL>  insert into t select rownum,'1111111111' from dba_objects where rownum<50000;

49999 rows created.

SQL>  insert into t select rownum,'1111111111' from dba_objects where rownum<50000;

49999 rows created.

SQL>  insert into t select rownum,'1111111111' from dba_objects where rownum<50000;
 insert into t select rownum,'1111111111' from dba_objects where rownum<50000
*
ERROR at line 1:
ORA-01653: unable to extend table SYS.T by 128 in tablespace TEST


SQL> commit;

Commit complete.


--4.从这里可以看出该文件最大可以使用7M
SQL> select bytes/1024/1024,maxbytes/1024/1024 from dba_data_files where file_id=5;

BYTES/1024/1024 MAXBYTES/1024/1024
--------------- ------------------
              7         32767.9844

--5.extents最大可占用6M的空间
SQL> select sum(bytes/1024/1024) from dba_extents where segment_name ='T';

SUM(BYTES/1024/1024)
--------------------
                   6

SQL> select sum(bytes/1024/1024) from dba_segments where segment_name ='T';

SUM(BYTES/1024/1024)
--------------------
                   6

--6.增大 lv空间后，才能使用到8M的空间。
[root@master ~]#  lvextend -l +1 /dev/VolOracle/test
  Extending logical volume test to 12.00 MB
  Logical volume test successfully resized

结论：使用raw设备时，文件可用空间要稍微小于raw设备的大小。
 

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