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zpool add/remove\r\n\r\n\r\n 在zpool create/destroy一节中,我们讲了怎样创建和删除一个pool。我们之所以说ZFS简单易用,就是它把系统管理员从复杂而繁琐的管理工作中解放出来,从而将更多的时间花在系统的整体构架上,而不是被日常的管理束缚住手脚和头脑。记得九月份在上海出差参加Sun Tech Days活动,在展台上和很多来自各个行业的软件开发者,系统管理员,系统工程师聊。大家有一个共同的认识就是,现在的volume management + 文件系统的管理方式在做系统扩充和缩小时非常复杂,常常为此提前要做各方面的准备,实施计划,操作流程,回退计划等等。而且,往往这些操作需要宕机做offline工作。我想有过这方面经验的人大概都会有这样的经历。\r\n\r\n 那么,现在我们有了新的选择:ZFS。我们叫ZFS为文件系统,其实ZFS是集volume management和文件系统功能于一体。对于用户来说,它的volume management功能是透明的。ZFS提供了两个简单的命令add/remove来解决系统扩充和缩小需要。而且,一切都是online操作,一切在线业务都不需要停机。zfs add/remove语法如下:\r\n\r\n\r\n\r\n--------------------------------------------------------------------------------\r\n\r\nzpool add [-fn] pool vdev ...\r\n\r\nzpool remove pool vdev\r\n\r\n\r\n\r\n--------------------------------------------------------------------------------\r\n\r\n 注:当前remove操作只支持对hot spares设备的删除。\r\n\r\n 我们做一些实验,实验系统环境如下:\r\n\r\n# format\r\nSearching for disks...done\r\n\r\n\r\nAVAILABLE DISK SELECTIONS:\r\n 0. c1t0d0 <SUN36G cyl 24620 alt 2 hd 27 sec 107>\r\n /pci@8,600000/SUNW,qlc@2/fp@0,0/ssd@w21000004cf836e64,0\r\n 1. c1t2d0 <SEAGATE-ST336605FSUN36G-0438-33.92GB>\r\n /pci@8,600000/SUNW,qlc@2/fp@0,0/ssd@w21000004cf836e65,0\r\n 2. c1t3d0 <SEAGATE-ST336605FSUN36G-0438-33.92GB>\r\n /pci@8,600000/SUNW,qlc@2/fp@0,0/ssd@w21000004cf836e6a,0\r\n 3. c1t4d0 <SEAGATE-ST336605FSUN36G-0438-33.92GB>\r\n /pci@8,600000/SUNW,qlc@2/fp@0,0/ssd@w21000004cf836e60,0\r\n 4. c2t1d0 <SEAGATE-ST318404LSUN18G-4207-16.87GB>\r\n /pci@9,700000/scsi@3/sd@1,0\r\n 5. c2t2d0 <SEAGATE-ST318404LSUN18G-4207-16.87GB>\r\n /pci@9,700000/scsi@3/sd@2,0\r\n 6. c2t4d0 <SEAGATE-ST318404LSUN18G-4207-16.87GB>\r\n /pci@9,700000/scsi@3/sd@4,0\r\n 7. c2t5d0 <SEAGATE-ST318404LSUN18G-4207-16.87GB>\r\n /pci@9,700000/scsi@3/sd@5,0 \r\n1. 建立一个pool,然后再增加其空间一倍。\r\n\r\n# zpool create mypool c2t5d0\r\n# zfs list\r\nNAME USED AVAIL REFER MOUNTPOINT\r\nmypool 85K 16.5G 24.5K /mypool\r\n# zpool add mypool c2t4d0\r\n# zfs list\r\nNAME USED AVAIL REFER MOUNTPOINT\r\nmypool 88K 33.0G 24.5K /mypool\r\n\r\n 我们可以看到,再mypool增加了一个新的disk后空间从16.5G变为33.0G。\r\n\r\n# zpool status -v mypool\r\n pool: mypool\r\n state: ONLINE\r\n scrub: none requested\r\nconfig:\r\n\r\n NAME STATE READ WRITE CKSUM\r\n mypool ONLINE 0 0 0\r\n c2t5d0 ONLINE 0 0 0\r\n c2t4d0 ONLINE 0 0 0\r\n\r\nerrors: No known data errors\r\n\r\n 我们可以从上面zpool status的输出清晰的看出mypool的盘结构。\r\n\r\n # zpool destroy mypool\r\n\r\n\r\n 删除mypool\r\n\r\n\r\n2. 建立一个2路的mirror,再为其扩充空间。\r\n\r\n\r\n\r\n# zpool destroy mymirror\r\n# zpool create mymirror mirror c2t1d0 c2t2d0\r\n# zfs list\r\nNAME USED AVAIL REFER MOUNTPOINT\r\nmymirror 86K 16.5G 24.5K /mymirror\r\n# zpool status mymirror\r\n pool: mymirror\r\n state: ONLINE\r\n scrub: none requested\r\nconfig:\r\n\r\n NAME STATE READ WRITE CKSUM\r\n mymirror ONLINE 0 0 0\r\n mirror ONLINE 0 0 0\r\n c2t1d0 ONLINE 0 0 0\r\n c2t2d0 ONLINE 0 0 0\r\n\r\nerrors: No known data errors\r\n\r\n\r\n 两个大小分别为16G的硬盘构成一个2路的mirror,容积仍然为16G。\r\n\r\n# zpool add mymirror mirror c2t4d0 c2t5d0\r\n# zpool status mymirror\r\n pool: mymirror\r\n state: ONLINE\r\n scrub: none requested\r\nconfig:\r\n\r\n NAME STATE READ WRITE CKSUM\r\n mymirror ONLINE 0 0 0\r\n mirror ONLINE 0 0 0\r\n c2t1d0 ONLINE 0 0 0\r\n c2t2d0 ONLINE 0 0 0\r\n mirror ONLINE 0 0 0\r\n c2t4d0 ONLINE 0 0 0\r\n c2t5d0 ONLINE 0 0 0\r\n\r\nerrors: No known data errors\r\n# zfs list\r\nNAME USED AVAIL REFER MOUNTPOINT\r\nmymirror 88K 33.0G 24.5K /mymirror\r\n\r\n\r\n 结果显而易见,mymirror的大小变为33G。 \r\n\r\n\r\n# zpool destroy mymirror\r\n\r\n \r\n\r\n3. 建立一个raidz池,增加hot spares设备,然后删除。\r\n\r\n# zpool create mypool raidz c2t1d0 c2t2d0 c2t4d0 spare c2t5d0\r\n# zfs list\r\nNAME USED AVAIL REFER MOUNTPOINT\r\nmypool 102K 33.1G 32.6K /mypool\r\n# zpool status mypool\r\n pool: mypool\r\n state: ONLINE\r\n scrub: none requested\r\nconfig:\r\n\r\n NAME STATE READ WRITE CKSUM\r\n mypool ONLINE 0 0 0\r\n raidz1 ONLINE 0 0 0\r\n c2t1d0 ONLINE 0 0 0\r\n c2t2d0 ONLINE 0 0 0\r\n c2t4d0 ONLINE 0 0 0\r\n spares\r\n c2t5d0 AVAIL\r\n\r\nerrors: No known data errors\r\n\r\n 对于raidz/raidz1/raidz2来说,整个池的大小等于(N-P) * min(disk size)。N表示disk个数,P为冗余盘的个数,即1或者2。raidz是raidz1的alias。关于数据冗余,我会在以后专门拿出来讨论。hot spares设备不计入池空间。\r\n\r\n\r\n# zpool remove mypool c2t5d0\r\n hot spares设备被删除。 \r\n\r\n# zpool status mypool\r\n pool: mypool\r\n state: ONLINE\r\n scrub: none requested\r\nconfig:\r\n\r\n NAME STATE READ WRITE CKSUM\r\n mypool ONLINE 0 0 0\r\n raidz1 ONLINE 0 0 0\r\n c2t1d0 ONLINE 0 0 0\r\n c2t2d0 ONLINE 0 0 0\r\n c2t4d0 ONLINE 0 0 0\r\n\r\nerrors: No known data errors\r\n# zfs list\r\nNAME USED AVAIL REFER MOUNTPOINT\r\nmypool 102K 33.1G 32.6K /mypool\r\n\r\n# zpool destroy mypool\r\n\r\n\r\n add/remove是对整个池的大小的修改,但如果我想将一个简单的stripe文件系统变成一个带冗余的mirror,该怎么办?或者想将一个3路mirror变成2路的又该如何?add/remove是没法做到这一点的。这就是我们下一次要探讨的zpool attach/detach。\r\n\r\nhttp://blogs.sun.com/forrest/ent ... _2_zpool_add_remove |
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