Software projects/OS/Slackware/Advanced usage/RAID

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Revision as of 19:04, 17 April 2012 by Linux-SWAT (talk | contribs) (RAID)
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WIP WIP WIP HURRAID

  • Need to properly rebuild one array while completing.

RAID

  • http://en.wikipedia.org/wiki/RAID
  • We will use the robust native Linux software RAID.
  • It's a feature that can be used on the Pandora, although not as useful than on a PC or a server, so let's have fun with it
  • I will cover here only a RAID 1 (mirror) on two SD cards, as it should be the more interesting for a server usage because under read load, you can reach about 27MB/s against 16MB/s on one card.
  • A SD + USB drive can also work although untested. As a two SD + USB drive.

Partitioning

  • So you have to partition your system SD card differently than the default SL4P setup.
  • In this example, we will use the recommended minimal 8G card for the slot 1.
  • You can use a different sized card for the right slot. The minimum size is 4G for this second card, and we will use 4G in this example.
  • The RAID 1 partitions must have the same exact size.

Card 1

  • Partition that way:

6G ext2 for the system 256M for the swap 1.5G unformated RAID

  • We left 256M free. NEVER fill an entire drive with a RAID array. Drives, ie. all 8G, doesn't necessary offer the same exact capacity, so you can get in trouble if you add a drive 32MB short.

Card 2

256M for the swap 1.5G unformated RAID 2G unused. Do what you want with it.

Create the RAID 1 array

Make the RAID permanent

Remove a drive from the array

  • It's likely to be the one in the right SD slot.

Repair the array

  • Depending the size of your RAID partition and he data on it, it can take a while.