Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Why can't add a hot spare?

# mfiutil add e1:s1 mfid0
mfiutil: Drive 1 is not available

I found the reason is e1:s1 is marked online, it must be Marked as an unconfigured good drive, and to mark that it must not be part of an existing array. Then what can i do to get the drive e1:s1 out of array??

# mfiutil show config
mfi0 Configuration: 1 arrays, 1 volumes, 0 spares

    array 0 of 2 drives:
        drive 0 (  137G) ONLINE <HITACHI HUS153014VLS300 A410 serial=JFWHSB4C> 
SAS enclosure 1, slot 0
        drive 1 (  137G) ONLINE <HITACHI HUS153014VLS300 A410 serial=JFWJ3AEC> 
SAS enclosure 1, slot 1

    volume mfid0 (136G) RAID-1 64K OPTIMAL spans:
        array 0
share|improve this question
Is it difficult or a bad question? – hamlet Jun 28 '11 at 0:08
up vote 0 down vote accepted

You've got the two drives in a mirror. If you take drive 1 out of the mirror and make it a spare, then you won't have a mirror anymore; and you can't add a spare to something that isn't an array to anymore.

One or more of: You're very much misunderstanding RAID, spares, missing a disk.

share|improve this answer
Thank you Chris! I have wait the answer two days.Thanks a lot! I am really a very beginner in RAID days before. – hamlet Jun 28 '11 at 5:05
If you mean i had a backup in driver 1 already? Files in drive 0 has a backup in driver 1? – hamlet Jun 28 '11 at 5:08
So I no need to setup a hot spare? Seems my server has a well-configured RAID1 in firmware. And RAID1 means: My Driver 1 is a mirror with Drive 0, no matter which driver breaks, another will replace it auto. Is my thought right? – hamlet Jun 28 '11 at 5:24
Correct, you have a RAID1 (mirror) running now; if one goes bad the other will continue working. RAID isn't a backup; if you delete files on the array, they're still gone; if the file system becomes corrupted, it's still gone. RAID protects you from hardware failure only. Separate backups to another computer, or disk drive, or backup tape are still necessary if you want your data to be backed up. – Chris S Jun 28 '11 at 12:22
Your explain is wonderful, and is so useful to me. Thanks you very much. – hamlet Jun 28 '11 at 14:49

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.