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Subject: gptids are not symlinks to /dev/da*
From: Chris Stankevitz <chrisstankevitz@gmail.com>
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Hello,

Can you help fill in some detail for the questions I list below?  Thank you!


Facts:

1. zpool status shows "gptids" like so:
gptid/affd7a1f-9c50-11e3-a81e-002590caf078

2. gptids are located under /dev/gptid/ and /dev

3. smartctl does not like gptids but does like /dev/da* "smartctl -a
/dev/gptid/affd7a1f-9c50-11e3-a81e-002590caf078"

4. "man gptid" comes up blank

5. the freebsd handbook does not describe gptid

6. google "freebsd gptid" returns a bunch of random stuff


Questions:

Q1: What is a gptid?

A1: It's some kind of system by which drives have the same device name
across reboots


Q2: How does FreeBSD know which drive corresponds to which gptid?
When is the gptid assigned?

A2: gptids are written to the first block of the disk during manufacture.


Q3: Can I use it like a regular /dev/da? device?

A3: No.  For example, smartctl takes /dev/da* but not /dev/gptid/*


Q4: So gptid is not like the linux symlinks called /dev/disk/by-uuid/*

Q4. Apparently not.


Q5: Why am I unable to figure out what is a gptid even after
attempting to read documentation/google?

A5: Maybe you aren't trying hard enough.



Thank you!

Chris