Differences

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--- raid [2009/09/30 05:09] – 172.26.0.166
+++ raid [2009/11/16 13:59] – 172.26.0.166
@@ Line 5: / Line 5: @@
 ==== Drive numbering ====
-If you're looking at the front of the HPC you'll see four rows of drives.  From the bottom;
+If you're looking at the front of the HPC you'll see four rows of drives.  From the bottom:
   * Rows 0 - 2 are SATA, connected to the hardware 3ware RAID card
   * Row 3 are IDE
@@ Line 50: / Line 50: @@
 unused devices: <none></code>
+==== Repair RAID ====
+Setting a disk faulty/failed:
+# mdadm --fail /dev/md0 /dev/hdc1
+DO NOT run this every on a raid0 or linear device or your data is toasted!
+Removing a faulty disk from an array:
+# mdadm --remove /dev/md0 /dev/hdc1
+Clearing any previous raid info on a disk (eg. reusing a disk from another decommissioned raid array)
+# mdadm --zero-superblock /dev/hdc1
+Adding a disk to an array
+# mdadm --add /dev/md0 /dev/hdc1
 === To Do list: ===
@@ Line 65: / Line 84: @@
 ===== Hardware RAID =====
-There is a utility, tw_cli, which can be used to control the hardware raid.  The hardware RAID has three arrays, all RAID 5.  Each "unit" (row) is one array.
+A 3ware 9500S SATA RAID card using the 3w-9xxx kernel module.  It has 12 channels.  The HPC is configured to use RAID5 for all of its RAID arrays on the hardware RAID.
-| 8 | 9 | 10 | 11 |
+==== Physical Disk Layout ====
-| 4 | 5 | 6 | 7 |
-| 0 | 1 | 2 | 3 |
+We have one RAID controller, 'c1'.  Disks are plugged into ports, 'p1' - 'p11'.  The disks are then grouped into units (basically the rows), 'u0' - 'u2'.
+| Port 8 | Port 9 | Port 10 | Port 11 |
+| Port 4 | Port 5 | Port 6 | Port 7 |
+| Port 0 | Port 1 | Port 2 | Port 3 |
+==== Repairing 'degraded' arrays ====
+There is a utility, tw_cli, which can be used to control/monitor the hardware raid controller.
 Study the output of ''show'' to know which controller to manage.  Then you can use ''/c1 show'' to show the status of that particular controller.  Things to look for:
   * Which controller is active? (c0, c1, etc)
   * Which unit is degraded? (u0, u1, u2, etc)
-  * Which
+  * Which port is inactive or missing? (p1, p5, etc)
+<note warning>The controller supports hot swapping but you **must** remove a faulty drive through the ''tw_cli'' tool before you can swap drives.</note>
 Remove the faulty port: