Recovering a failed (SSD) hard drive. Unknown partition type.

[Sam Varshavchik]

linux guy writes:

> What are the chances that the drive controller in the laptop caused
> this problem ?
>
> I just tested the drive in the laptop BIOS and it says its fine.
> SMART and what it does for a surface scan.

Yes, I'm sure it's fine now. Looks to me like some pages went bad, and the  
drive mapped them out and replaced with some spare pages held in reserve.  
Unfortunately, the bad pages were mapped to the initial sectors that held  
the partition table and the bootloader.

The partition table is stored only in one place. There's no backup copy of  
it. I suppose that it's theoretically possible to scan the sectors looking  
for something that looks like the start of an ext4 partition. It'll probably  
be on sector 63 or 2048, and from the ext4 superblock figure out the  
partition's size, then past it scan for the next partition's ext4  
superblock, and be able to reconstruct the partition table that way. But I  
don't know of any tool that would do that.

In this respect, I say that SSDs are no better than mechnical drives. For  
peace of mind, nothing beats a pair of RAID-1 drives. One drive goes bad –  
it's easy to swap it out without losing any data.

Plus, when you have one of those once-in-a-biennial events like the old  
100mb for /boot not being big enough any more, or grub growing too fat to  
fit within the first 63 sectors, with RAID-1 you'll be able to sweat it out,  
and survive, without having to wipe everything and fresh-install from  
scratch.

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