Exadata is the Ferrari of the technology world. It’s considered the technology for the select few, but everyone dreams about it. There is very little information available on the Internet right now about the architecture and the administration of Exadata, though it’s a huge subject in itself, which demand numerous high quality books, dedicated blogs, websites and special interest groups.
This blog post just mentions some of very important components of Exadata Storage Server, which are physical disks, cell disks, grid disks and ASM disks and their correspondence.
The Exadata Storage Server contains 12 physical disks.
There is one to one relationship between a physical disk and the cell disk. One physical disk corresponds to a single cell disk.
Then a Grid disk comprises of many cell disks.
And a Grid disk corresponds to one ASM disk.
An ASM diskgroup comprises of many ASM disks.
On the Exadata Storage Server, We can use cellcli command line utility in Exadata to see the information about physical disks, cell disks, grid disks and the cell.
The cellcli utility works from the root, celladmin and cellmonitor (read-only) users. The best practice is actually to run it from the last two less-privileged users, and not from the root user.
Now let’s have look at some of the disk management commands using cellcli utility.
[root@mycell-net0 ~]# cellcli
CellCLI: Release 220.127.116.11.1 - Production on Fri Oct 29 07:47:26 GMT 2010
Copyright (c) 2007, 2009, Oracle. All rights reserved.
Cell Efficiency Ratio: 140
Just to give you an idea about what cellcli has on offer, look at the output of the help command:
Let’s see the output of some of the commands listed above:
CellCLI> list physicaldisk detail
makeModel: "MARVELL SD88SA02"
slotNumber: "PCI Slot: 1; FDOM: 2"
CellCLI> list cell detail
makeModel: SUN MICROSYSTEMS SUN FIRE X4275 SERVER SAS
CellCLI> list celldisk detail
CellCLI> list griddisk detail
In the future posts, I will be touching the administration of celldisks, as how to perform operations like (import/export/create/drop/alter) on the celldisks.
The post was originally published by me at Pythian's Blog
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