Sun Fire & SAS drive replacement - FreeBSD
==================================================================


Had to replace a disk drive in a Sun Fire server. I purchased a 12G/s drive
and didn't know if it would be working in this old Sun folk. It did, with
negotiated 3G/s speed. I run into problems with Adaptec and low-level
format. This is how to solve them.



Adaptec
==========

First thing you need to do is to add drive using Adaptec utility.

Sun provided concise manual for that. 


Press Ctrl+A during boot.

Go to Array Configuration Utility

Initialize Drives

- "Insert" key doesn't work using remote terminal via Ilom. In Gnome
  Terminal, you may switch off Keyboard Shorcuts in Preferences. Then
  Shift+Insert key worked. In other case, it didn't.

- By monkey-typing I found you can use "a" instead of the "Insert" key 

- add the drive to the inicialization list and press Enter. Or press
  Backspace (Delete) if you added a drive by accident.


Create Array
- I use ZFS mirror, so the mirroring won't be job of Adaptec

- create array - type: volume, read caching: NO!, write caching: NO!, Create
  RAID via: Skip Init

- leaving caching ON caused later read & write errors using FreeBSD, which
  degraded the system state & forced me to hard-reset the stucked machine. 
  Don't use the Adaptec caching.  Furthermore, Write Cache is dependent on
  the battery of Adaptec, which may not be present or functional. Even
  official Sun documentation of that time suggests that Adaptec caching is
  not a good idea.



Low-level format problem
================================

- out of desperation, I tried also a low-level format from Adaptec
  utilities. Because server was in boot state and Adaptec stated it may last
  for many hours, I canceled the process. That made the disk unreadable and
  invisible for both Adaptec and system.

- Western Digital, the current owner of HGST had provided a 474-pages
  specification for the family of it's SAS drives
  
- according to that, the low-level format is not business of the
  Adapte[c|r], but of a command run by disk itself

- seems that SCSI / SAS drives are quite intelligent and able to do a lot of
  management and reporting

- in case of unfinished low-level format, disk is in "Format Degraded"
  state and doesn't permit read and write operations

- fortunately, I found FreeBSD port sysutils/sg3_utils 
  which provides many tools for low-level commanding and debugging SCSI
  devices, sg_format being one of them

- disk remained visible for freebsd's camcontrol as a "pass" device:
  camcontrol devlist
  (drive name was pass3, in my case)

- sg_logs pass3 -a
  prints out a lot of debug info about the drive

- camcontrol format pass3
  (maybe with option -w , see man camcontrol)
  did re-start the lowlevel format for me

- could be done by sg_format as well - see man sg_format - but didn't work
  in my case

- you can watch progress of internal formatting by 
  camcontrol sense pass3 -v
  (lasted several hours for 1.2 TB drive)

- once low-level formatting is finished, drive is no more in "Format Degraded"
  state and could be detected by Adaptec as in the beginning of this guide


EOF

Comments requested

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