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--- linux:raid [2013/03/15 16:58]
admin
+++ linux:raid [2017/02/23 15:18]
solovyanov [Setting up RAID10 with tw_cli]
@@ Line 27: / Line 27: @@
   mdadm: ... critical section passed.
   #
+</code>
+**Nekdy se muze hodit:**
+tags: 3ware tw_cli replace drive
+<code>
+echo "0 0 0" > /sys/bus/scsi/devices/0\:0\:4\:0/rescan
 </code>
 ===== Links =====
   * [[http://www.debian-administration.org/articles/238| Migrating To RAID1 Mirror on Sarge]]
   * [[http://lucasmanual.com/mywiki/DebianRAID|Debian RAID]]
+======== Frozen spare ========
+<code>
+# mdadm --detail /dev/md0
+/dev/md0:
+        Version : 1.2
+  Creation Time : Sat Feb  2 06:51:55 2013
+     Raid Level : raid6
+     Array Size : 11717889024 (11175.05 GiB 11999.12 GB)
+  Used Dev Size : 1952981504 (1862.51 GiB 1999.85 GB)
+   Raid Devices : 8
+  Total Devices : 8
+    Persistence : Superblock is persistent
+    Update Time : Mon Jul 15 20:30:57 2013
+          State : active, degraded
+ Active Devices : 7
+Working Devices : 8
+ Failed Devices : 0
+  Spare Devices : 1
+         Layout : left-symmetric
+     Chunk Size : 512K
+           Name : tukan2:0  (local to host tukan2)
+           UUID : bf36da8d:5009d151:4f3ee49d:92059128
+         Events : 1535927
+    Number   Major   Minor   RaidDevice State
+       8       17        0      active sync   /dev/sdb1
+       8       33        1      active sync   /dev/sdc1
+       8       49        2      active sync   /dev/sdd1
+       8       65        3      active sync   /dev/sde1
+       8       97        4      active sync   /dev/sdg1
+       0        0        5      removed
+       8      129        6      active sync   /dev/sdi1
+       8      145        7      active sync   /dev/sdj1
+       8      113        -      spare   /dev/sdh1
+</code>
+   # cat /sys/block/md0/md/sync_action
+   frozen
+   echo repair >/sys/block/md0/md/sync_action
+**Result**:
+<code>
+# mdadm --detail /dev/md0
+/dev/md0:
+        Version : 1.2
+  Creation Time : Sat Feb  2 06:51:55 2013
+     Raid Level : raid6
+     Array Size : 11717889024 (11175.05 GiB 11999.12 GB)
+  Used Dev Size : 1952981504 (1862.51 GiB 1999.85 GB)
+   Raid Devices : 8
+  Total Devices : 8
+    Persistence : Superblock is persistent
+    Update Time : Mon Jul 15 20:38:59 2013
+          State : active, degraded, recovering
+ Active Devices : 7
+Working Devices : 8
+ Failed Devices : 0
+  Spare Devices : 1
+         Layout : left-symmetric
+     Chunk Size : 512K
+ Rebuild Status : 0% complete
+           Name : tukan2:0  (local to host tukan2)
+           UUID : bf36da8d:5009d151:4f3ee49d:92059128
+         Events : 1536481
+    Number   Major   Minor   RaidDevice State
+       8       17        0      active sync   /dev/sdb1
+       8       33        1      active sync   /dev/sdc1
+       8       49        2      active sync   /dev/sdd1
+       8       65        3      active sync   /dev/sde1
+       8       97        4      active sync   /dev/sdg1
+       8      113        5      spare rebuilding   /dev/sdh1
+       8      129        6      active sync   /dev/sdi1
+       8      145        7      active sync   /dev/sdj1
+</code>
+====== Speed Up ======
+<code>
+ echo     6144 > /sys/block/md3/md/stripe_cache_size
+ echo   40000 > /proc/sys/dev/raid/speed_limit_min
+ echo 256000 > /proc/sys/dev/raid/speed_limit_max
+</code>
 ====== 3ware Utility ======
@@ Line 56: / Line 155: @@
   ctrl slot=0 create type=ld drives=1I:1:3 raid=0
  </code>
+====== RAID10 performance ======
+    mdadm -v --create /dev/md0 --level=raid10 --layout=f2 --raid-devices=4 ...
+The trick is "layout=f2" as the man page says>
+''  Finally, the layout options for RAID10 are one of 'n', 'o' or 'f' followed by a small number.  The default is 'n2'.  The supported options are:
+              'n' signals 'near' copies.  Multiple copies of one data block are at similar offsets in different devices.
+              'o' signals 'offset' copies.  Rather than the chunks being duplicated within a stripe, whole stripes are duplicated but are rotated by  one  device  so
+              duplicate blocks are on different devices.  Thus subsequent copies of a block are in the next drive, and are one chunk further down.
+              'f' signals 'far' copies (multiple copies have very different offsets).  See md(4) for more detail about 'near', 'offset', and 'far'.
+              The  number is the number of copies of each datablock.  2 is normal, 3 can be useful.  This number can be at most equal to the number of devices in the
+              array.  It does not need to divide evenly into that number (e.g. it is perfectly legal to have an 'n2' layout for  an  array  with  an  odd  number  of
+              devices).
+''
+====== Setting up RAID10 with tw_cli ======
+Generating the RAID10 field with disks in ports from 8 to 17:
+  ./tw_cli /c0 add type=raid10 disk=8-17 noautoverify
+Software way of removing a disk from port 14:
+  ./tw_cli maint remove c0 p14
+Taking a look of what has it done:
+  ./tw_cli /c0/u0 show
+"Adding" a disk back to the file system (more like identifying it):
+  ./tw_cli maint rescan c0
+Starting the verification process (if the unit was not previously initialized, it will be):
+  ./tw_cli /c0/u0 start verify
+If you need to check which disk is connected to each port, you can use this command, it will light the external GUI light:
+  ./tw_cli /c0/p16 set identify=on
+Problem: after physically removing a disk and installing it back, RAID started re-initializing by its own will without letting the master know. It's just bad.

linux/raid.txt · Last modified: 2017/03/20 11:51 by tomsa