gptids are not symlinks to /dev/da*
wblock at wonkity.com
Mon Feb 24 19:26:06 UTC 2014
On Mon, 24 Feb 2014, Chris Stankevitz wrote:
> Can you help fill in some detail for the questions I list below? Thank you!
> 1. zpool status shows "gptids" like so:
> 2. gptids are located under /dev/gptid/ and /dev
> 3. smartctl does not like gptids but does like /dev/da* "smartctl -a
> 4. "man gptid" comes up blank
> 5. the freebsd handbook does not describe gptid
> 6. google "freebsd gptid" returns a bunch of random stuff
> Q1: What is a gptid?
> A1: It's some kind of system by which drives have the same device name
> across reboots
Not device name, but a label. Although the correct one should work in
place of a device name. I use GPT partition labels, but have never
bothered with the GUIDs.
> 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.
Generated when the structure is created, I think.
> Q3: Can I use it like a regular /dev/da? device?
> A3: No. For example, smartctl takes /dev/da* but not /dev/gptid/*
smartctl wants a device, but GPTIDs refer to partitions. There is a
GUID for the whole disk, but it appears to not be shown.
> Q5: Why am I unable to figure out what is a gptid even after
> attempting to read documentation/google?
GPT IDs and labels are created by the geom_label class, described in
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