[Klug-general] Software Vs Hardware Raid

[Paul Littlefield]

On Thursday 03 July 2008 16:24:07 J D Freeman wrote:
> These days linux software raid is your best option.


Yes, I have to agree. Used it for years now and it seems the best trade-off.

There is a slight performance hit with RAID 1 (mirroring) but the piece-of-mind outways that.

Here is some RAID output from one of my clients' servers. It has 5 drives which comprise: 2 in use, 2 hot 
spares and 1 cold spare in the case ready to go.

server2 ~ # cat /proc/mdstat
Personalities : [raid1]
md1 : active raid1 sdd1[2](S) sdc1[3](S) sdb1[1] sda1[0]
      24000 blocks [2/2] [UU]

md2 : active raid1 sdd2[2](S) sdc2[3](S) sdb2[1] sda2[0]
      987904 blocks [2/2] [UU]

md3 : active raid1 sdd3[2](S) sdc3[3](S) sdb3[1] sda3[0]
      48837504 blocks [2/2] [UU]

md4 : active raid1 sdd4[2](S) sdc4[3](S) sdb4[1] sda4[0]
      194346240 blocks [2/2] [UU]



It also has SMART health monitoring on the SATA drives themselves:-

server2 ~ # smartctl -d ata -H /dev/sda
smartctl version 5.37 [x86_64-pc-linux-gnu] Copyright (C) 2002-6 Bruce Allen
Home page is http://smartmontools.sourceforge.net/

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED
Please note the following marginal Attributes:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
190 Temperature_Celsius     0x0022   067   045   045    Old_age   Always   In_the_past 33



Hope this helps.

Regards

PAULLY