Greenplum支持表空间，创建表空间时，需要指定filespace。
postgres=# \h create tablespace;
Command:     CREATE TABLESPACE
Description: define a new tablespace
Syntax:
CREATE TABLESPACE tablespace_name [OWNER username] FILESPACE filespace_name那么什么是filespace呢？
GP在初始化完后，有一个默认的filespace ： pg_system。
表空间pg_default和pg_global都放在这个filespace下面。
也就是说一个filespace可以被多个表空间使用。
postgres=# select oid,* from pg_filespace;oid  |  fsname   | fsowner
------+-----------+---------3052 | pg_system |      10
(1 row)
postgres=# select * from pg_tablespace;spcname   | spcowner | spclocation | spcacl | spcprilocations | spcmirlocations | spcfsoid
------------+----------+-------------+--------+-----------------+-----------------+----------pg_default |       10 |             |        |                 |                 |     3052pg_global  |       10 |             |        |                 |                 |     3052
(2 rows)还有TEMPORARY_FILES和TRANSACTION_FILES对应的filespace如下：
$gpfilespace --showtempfilespace
20151218:16:02:07:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-
A tablespace requires a file system location to store its database
files. A filespace is a collection of file system locations for all components
in a Greenplum system (primary segment, mirror segment and master instances).
Once a filespace is created, it can be used by one or more tablespaces.20151218:16:02:07:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-Getting filespace information for TEMPORARY_FILES
20151218:16:02:08:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-Checking for filespace consistency
20151218:16:02:08:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-Obtaining current filespace entries used by TEMPORARY_FILES
20151218:16:02:09:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-TEMPORARY_FILES OIDs are consistent for pg_system filespace
20151218:16:02:11:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-TEMPORARY_FILES entries are consistent for pg_system filespace
20151218:16:02:11:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-Obtaining current filespace entries used by TEMPORARY_FILES
20151218:16:02:11:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-Current Filespace for TEMPORARY_FILES is pg_system
20151218:16:02:11:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-1    /disk1/digoal/gpdata/gpseg-1
20151218:16:02:11:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-25    /disk1/digoal/gpdata_mirror/gpseg0
20151218:16:02:11:063949 gpfilespace:127.0.0.1:digoal-[INFO]:-2    /disk1/digoal/gpdata/gpseg0
......$gpfilespace --showtransfilespace
20151218:16:09:41:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-
A tablespace requires a file system location to store its database
files. A filespace is a collection of file system locations for all components
in a Greenplum system (primary segment, mirror segment and master instances).
Once a filespace is created, it can be used by one or more tablespaces.20151218:16:09:41:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-Getting filespace information for TRANSACTION_FILES
20151218:16:09:41:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-Checking for filespace consistency
20151218:16:09:41:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-Obtaining current filespace entries used by TRANSACTION_FILES
20151218:16:09:42:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-TRANSACTION_FILES OIDs are consistent for pg_system filespace
20151218:16:09:44:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-TRANSACTION_FILES entries are consistent for pg_system filespace
20151218:16:09:44:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-Obtaining current filespace entries used by TRANSACTION_FILES
20151218:16:09:44:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-Current Filespace for TRANSACTION_FILES is pg_system
20151218:16:09:44:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-1    /disk1/digoal/gpdata/gpseg-1
20151218:16:09:44:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-25    /disk1/digoal/gpdata_mirror/gpseg0
20151218:16:09:44:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-2    /disk1/digoal/gpdata/gpseg0
20151218:16:09:44:071104 gpfilespace:127.0.0.1:digoal-[INFO]:-26    /disk1/digoal/gpdata_mirror/gpseg1
......如果我们的greenplum集群中，有SSD硬盘，又有SATA硬盘。怎样更好的利用这些空间呢？
方法1.
用flashcache或bcache，通过device mapper技术，将SSD和SATA绑定，做成块设备。
再通过 逻辑卷管理 或者 软RAID 或者 brtfs or zfs管理起来，做成大的文件系统。
（还有一种方法是用RHEL 7提供的LVM，可以将SSD作为二级缓存）
这种方法对GP来说，是混合动力，可以创建一个或多个文件系统（都具备混合动力）。
所以建议只需要一个pg_system filespace就够了(除非容量到了文件系统管理的极限，那样的话可以分成多个文件系统)。
用多个文件系统的情况下，就需要对每个文件系统，创建对应的目录，以及filespace。方法2.
SSD和SATA分开，各自创建各自的文件系统。
对每个文件系统，创建对应的目录，以及filespace。创建filespace非常简单，分几步。
如下：
1. 创建目录，需要在所有的角色对应的主机中创建。给予gp 操作系统管理用户对应的权限。
master
$ mkdir /ssd1/gpdata/master_p
$ chown gpadmin:gpadmin /ssd1/gpdata/master_pmaster standby
$ mkdir /ssd1/gpdata/master_s
$ chown gpadmin:gpadmin /ssd1/gpdata/master_ssegment
$ mkdir /ssd1/gpdata_p
$ chown gpadmin:gpadmin /ssd1/gpdata_psegment mirror
$ mkdir /ssd1/gpdata_s
$ chown gpadmin:gpadmin /ssd1/gpdata_s2. 查看系统配置
postgres=# select dbid,content,role,preferred_role,hostname,port from gp_segment_configuration order by role,dbid;dbid | content | role | preferred_role |     hostname      | port
------+---------+------+----------------+-------------------+-------2 |       0 | m    | p              | digoal.sqa.zmf | 400003 |       1 | m    | p              | digoal.sqa.zmf | 400014 |       2 | m    | p              | digoal.sqa.zmf | 400025 |       3 | m    | p              | digoal.sqa.zmf | 400036 |       4 | m    | p              | digoal.sqa.zmf | 400047 |       5 | m    | p              | digoal.sqa.zmf | 400058 |       6 | m    | p              | digoal.sqa.zmf | 400069 |       7 | m    | p              | digoal.sqa.zmf | 4000710 |       8 | m    | p              | digoal.sqa.zmf | 4000811 |       9 | m    | p              | digoal.sqa.zmf | 4000912 |      10 | m    | p              | digoal.sqa.zmf | 4001013 |      11 | m    | p              | digoal.sqa.zmf | 4001114 |      12 | m    | p              | digoal.sqa.zmf | 4001215 |      13 | m    | p              | digoal.sqa.zmf | 4001316 |      14 | m    | p              | digoal.sqa.zmf | 4001417 |      15 | m    | p              | digoal.sqa.zmf | 4001518 |      16 | m    | p              | digoal.sqa.zmf | 4001619 |      17 | m    | p              | digoal.sqa.zmf | 4001720 |      18 | m    | p              | digoal.sqa.zmf | 4001821 |      19 | m    | p              | digoal.sqa.zmf | 4001922 |      20 | m    | p              | digoal.sqa.zmf | 4002023 |      21 | m    | p              | digoal.sqa.zmf | 4002124 |      22 | m    | p              | digoal.sqa.zmf | 500111 |      -1 | p    | p              | digoal.sqa.zmf |  192125 |       0 | p    | m              | digoal.sqa.zmf | 4100026 |       1 | p    | m              | digoal.sqa.zmf | 4100127 |       2 | p    | m              | digoal.sqa.zmf | 4100228 |       3 | p    | m              | digoal.sqa.zmf | 4100329 |       4 | p    | m              | digoal.sqa.zmf | 4100430 |       5 | p    | m              | digoal.sqa.zmf | 4100531 |       6 | p    | m              | digoal.sqa.zmf | 4100632 |       7 | p    | m              | digoal.sqa.zmf | 4100733 |       8 | p    | m              | digoal.sqa.zmf | 4100834 |       9 | p    | m              | digoal.sqa.zmf | 4100935 |      10 | p    | m              | digoal.sqa.zmf | 4101036 |      11 | p    | m              | digoal.sqa.zmf | 4101137 |      12 | p    | m              | digoal.sqa.zmf | 4101238 |      13 | p    | m              | digoal.sqa.zmf | 4101339 |      14 | p    | m              | digoal.sqa.zmf | 4101440 |      15 | p    | m              | digoal.sqa.zmf | 4101541 |      16 | p    | m              | digoal.sqa.zmf | 4101642 |      17 | p    | m              | digoal.sqa.zmf | 4101743 |      18 | p    | m              | digoal.sqa.zmf | 4101844 |      19 | p    | m              | digoal.sqa.zmf | 4101945 |      20 | p    | m              | digoal.sqa.zmf | 4102046 |      21 | p    | m              | digoal.sqa.zmf | 4102147 |      22 | p    | m              | digoal.sqa.zmf | 41022
(47 rows)3. 创建配置文件，格式如下，假如我要创建一个名为ssd1的filespace。
字段包含(hostname, dbid, DIR/$prefix + $content)
$ vi conf
filespace:ssd1
digoal.sqa.zmf:1:/ssd1/gpdata/master_p/gp-1
digoal.sqa.zmf:2:/ssd1/gpdata_p/gp0
digoal.sqa.zmf:3:/ssd1/gpdata_p/gp1
......
digoal.sqa.zmf:25:/ssd1/gpdata_s/gp0
digoal.sqa.zmf:26:/ssd1/gpdata_s/gp1
......还有一种方法是使用gpfilespace -o conf来生成配置文件。(在提示时输入目录名DIR的部分即可)4. 创建filespace
gpfilespace -c conf -h 127.0.0.1 -p 1921 -U digoal -W digoal20151218:17:16:39:108364 gpfilespace:127.0.0.1:digoal-[INFO]:-Connecting to database
20151218:17:16:39:108364 gpfilespace:127.0.0.1:digoal-[INFO]:-Filespace "ssd1" successfully created
......
然后gpfilespace会自动在数据库执行以下DDL SQL。创建对应的filespace。
所以我们也可以自己在数据库中执行SQL来创建filespace。CREATE FILESPACE ssd1
(1: '/disk1/digoal/new_p/gp-1',2: '/disk1/digoal/new_p/gp0',3: '/disk1/digoal/new_p/gp1',4: '/disk1/digoal/new_p/gp2',5: '/disk1/digoal/new_p/gp3',6: '/disk1/digoal/new_p/gp4',7: '/disk1/digoal/new_p/gp5',8: '/disk1/digoal/new_p/gp6',9: '/disk1/digoal/new_p/gp7',10: '/disk1/digoal/new_p/gp8',11: '/disk1/digoal/new_p/gp9',12: '/disk1/digoal/new_p/gp10',13: '/disk1/digoal/new_p/gp11',14: '/disk1/digoal/new_p/gp12',15: '/disk1/digoal/new_p/gp13',16: '/disk1/digoal/new_p/gp14',17: '/disk1/digoal/new_p/gp15',18: '/disk1/digoal/new_p/gp16',19: '/disk1/digoal/new_p/gp17',20: '/disk1/digoal/new_p/gp18',21: '/disk1/digoal/new_p/gp19',22: '/disk1/digoal/new_p/gp20',23: '/disk1/digoal/new_p/gp21',24: '/disk1/digoal/new_p/gp22',25: '/disk1/digoal/new_s/gp0',26: '/disk1/digoal/new_s/gp1',27: '/disk1/digoal/new_s/gp2',28: '/disk1/digoal/new_s/gp3',29: '/disk1/digoal/new_s/gp4',30: '/disk1/digoal/new_s/gp5',31: '/disk1/digoal/new_s/gp6',32: '/disk1/digoal/new_s/gp7',33: '/disk1/digoal/new_s/gp8',34: '/disk1/digoal/new_s/gp9',35: '/disk1/digoal/new_s/gp10',36: '/disk1/digoal/new_s/gp11',37: '/disk1/digoal/new_s/gp12',38: '/disk1/digoal/new_s/gp13',39: '/disk1/digoal/new_s/gp14',40: '/disk1/digoal/new_s/gp15',41: '/disk1/digoal/new_s/gp16',42: '/disk1/digoal/new_s/gp17',43: '/disk1/digoal/new_s/gp18',44: '/disk1/digoal/new_s/gp19',45: '/disk1/digoal/new_s/gp20',46: '/disk1/digoal/new_s/gp21',47: '/disk1/digoal/new_s/gp22'
);现在你可以使用这个filespace了.
例如
1. 将temp , trans移动到这个新的filespace.
$gpfilespace --movetempfilespace ssd120151218:17:17:29:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-
A tablespace requires a file system location to store its database
files. A filespace is a collection of file system locations for all components
in a Greenplum system (primary segment, mirror segment and master instances).
Once a filespace is created, it can be used by one or more tablespaces.20151218:17:17:29:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Database was started in NORMAL mode
20151218:17:17:29:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Stopping Greenplum Database
20151218:17:17:57:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Starting Greenplum Database in master only mode
20151218:17:18:02:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Checking if filespace ssd1 exists
20151218:17:18:02:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Checking if filespace is same as current filespace
20151218:17:18:02:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Stopping Greenplum Database in master only mode
20151218:17:18:04:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Checking for connectivity
20151218:17:18:04:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Obtaining current filespace information
20151218:17:18:04:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Obtaining current filespace entries used by TEMPORARY_FILES
20151218:17:18:04:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Obtaining segment information ...
20151218:17:18:04:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Creating RemoteOperations list
20151218:17:18:04:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Moving TEMPORARY_FILES filespace from pg_system to ssd1 ...
20151218:17:18:06:008363 gpfilespace:127.0.0.1:digoal-[INFO]:-Starting Greenplum Database$gpfilespace --movetransfilespace ssd1
...
20151218:17:19:17:055389 gpfilespace:127.0.0.1:digoal-[INFO]:-Moving TRANSACTION_FILES filespace from pg_system to ssd1 ...
20151218:17:21:16:055389 gpfilespace:127.0.0.1:digoal-[INFO]:-Starting Greenplum Database2. 创建表空间，使用这个filespace.
postgres=# create tablespace tbs_ssd1 filespace ssd1;
CREATE TABLESPACE
postgres=# create table tt(id int) tablespace tbs_ssd1;
NOTICE:  Table doesn't have 'DISTRIBUTED BY' clause -- Using column named 'id' as the Greenplum Database data distribution key for this table.
HINT:  The 'DISTRIBUTED BY' clause determines the distribution of data. Make sure column(s) chosen are the optimal data distribution key to minimize skew.
CREATE TABLE
postgres=# select * from pg_tablespace ;spcname   | spcowner | spclocation | spcacl | spcprilocations | spcmirlocations | spcfsoid
------------+----------+-------------+--------+-----------------+-----------------+----------pg_default |       10 |             |        |                 |                 |     3052pg_global  |       10 |             |        |                 |                 |     3052tbs_ssd1   |       10 |             |        |                 |                 |    69681
(3 rows)postgres=# select * from pg_filespace;fsname   | fsowner
-----------+---------pg_system |      10ssd1      |      10
(2 rows)greenplum为什么会引入filespace的概念？
因为主机目录结构可能不一样，所以原有的目录结构式的方法来创建表空间，可能不够灵活。最后，如何查看每个节点的filespace和location的关系？
digoal=# select a.dbid,a.content,a.role,a.port,a.hostname,b.fsname,c.fselocation from gp_segment_configuration a,pg_filespace b,pg_filespace_entry c where a.dbid=c.fsedbid and b.oid=c.fsefsoid order by content;dbid | content | role | port  |     hostname      |  fsname   |             fselocation
------+---------+------+-------+-------------------+-----------+--------------------------------------1 |      -1 | p    |  1921 | digoal193096.zmf | pg_system | /data01/gpdata/master_pgdata/gpseg-12 |       0 | p    | 40000 | digoal193096.zmf | pg_system | /data01/gpdata/gpseg03 |       1 | p    | 40001 | digoal193096.zmf | pg_system | /data01/gpdata/gpseg14 |       2 | p    | 40002 | digoal193096.zmf | pg_system | /data01/gpdata/gpseg25 |       3 | p    | 40000 | digoal199092.zmf | pg_system | /data01/gpdata/gpseg36 |       4 | p    | 40001 | digoal199092.zmf | pg_system | /data01/gpdata/gpseg47 |       5 | p    | 40002 | digoal199092.zmf | pg_system | /data01/gpdata/gpseg58 |       6 | p    | 40000 | digoal200164.zmf | pg_system | /data01/gpdata/gpseg69 |       7 | p    | 40001 | digoal200164.zmf | pg_system | /data01/gpdata/gpseg710 |       8 | p    | 40002 | digoal200164.zmf | pg_system | /data01/gpdata/gpseg811 |       9 | p    | 40000 | digoal204016.zmf | pg_system | /data01/gpdata/gpseg912 |      10 | p    | 40001 | digoal204016.zmf | pg_system | /data01/gpdata/gpseg1013 |      11 | p    | 40002 | digoal204016.zmf | pg_system | /data01/gpdata/gpseg1114 |      12 | p    | 40000 | digoal204063.zmf | pg_system | /data01/gpdata/gpseg1215 |      13 | p    | 40001 | digoal204063.zmf | pg_system | /data01/gpdata/gpseg1316 |      14 | p    | 40002 | digoal204063.zmf | pg_system | /data01/gpdata/gpseg1417 |      15 | p    | 40003 | digoal193096.zmf | pg_system | /data01/gpdata/gpseg1518 |      16 | p    | 40003 | digoal199092.zmf | pg_system | /data01/gpdata/gpseg1619 |      17 | p    | 40003 | digoal200164.zmf | pg_system | /data01/gpdata/gpseg1720 |      18 | p    | 40003 | digoal204016.zmf | pg_system | /data01/gpdata/gpseg1821 |      19 | p    | 40003 | digoal204063.zmf | pg_system | /data01/gpdata/gpseg1922 |      20 | p    | 40000 | digoal209198.zmf | pg_system | /data01/gpdata/gpseg2223 |      21 | p    | 40001 | digoal209198.zmf | pg_system | /data01/gpdata/gpseg2324 |      22 | p    | 40002 | digoal209198.zmf | pg_system | /data01/gpdata/gpseg2425 |      23 | p    | 40003 | digoal209198.zmf | pg_system | /data01/gpdata/gpseg25
(25 rows)[参考]
gpfilespace -h