Re: [LUG] OT: Reading single RAID 1 HD from failed array.

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Subject: Re: [LUG] OT: Reading single RAID 1 HD from failed array.

From: Simon Avery <digdilem@xxxxxxxxx>

Date: Sun, 4 Jun 2017 18:41:46 +0100

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Hi Julian,

The whole point of RAID 1 is that work continues as normal in a single HDD failure.

Synology device should continue working with one dead drive, if there are two and it's RAID 1. Read their support pages.

A lot depends on the software used to make the raid. mdadm is the most common linux software, and each drive can be mounted separately as a straight device, but hardware and fakeraid (BIOS software raid) can be wildly different and it's hard to know without more details. Not all RAID setups are equal, y'see.

HTH

On 3 June 2017 at 23:05, Julian Hall <linux@xxxxxxxxxxxx> wrote:

Hi All,

One of the two HDs in my Synology DS212j (RAID 1 array) has packed in, and the last time this happened I was still able to read the data on the other surviving disk. This time I was able to access it /once/ but not since - it refuses to mount at all. A friend mentioned he was able to read from a single RAID 1 disk after a crash in Linux but couldn't remember how; we've searched the forums all afternoon without success.

Any advice gratefully received.

Kind regards,

Julian

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