gjournal questions

Nicolas Blais nb_root at videotron.ca
Fri Mar 30 00:48:42 UTC 2007


Hi,

I've posted this here since this is probably the place to get an answer :) 
I've been experimenting with gjournal with the hopes of using it in my new 
multi-TB server (SuperMicro 5015M-NTB) . I have several questions, hopefully 
someone can help me out (long read though!).

1. I simulated a crash (hard power-off while transfering files). When I 
rebooted, I got the following on my console:

ad0: 78167MB <Maxtor 6Y080L0 YAR41BW0> at ata0-master UDMA133
acd0: DVDR <HL-DT-ST DVDRAM GSA-4163B/A105> at ata1-master UDMA33
ad4: 76319MB <Seagate ST3808110AS 3.AAE> at ata2-master SATA150
ad6: 76319MB <Seagate ST3808110AS 3.AAE> at ata3-master SATA150
ad10: 76319MB <Seagate ST380817AS 3.42> at ata5-master SATA150
GEOM_JOURNAL: Journal 2822006383: ad10s1 contains data.
GEOM_JOURNAL: Journal 2822006383: ad10s1 contains journal.
GEOM_JOURNAL: Journal ad10s1 clean.
acd0: FAILURE - INQUIRY ILLEGAL REQUEST asc=0x24 ascq=0x00 sks=0x40 0x00 0x01
ar0: 76293MB <Promise Fasttrak RAID1> status: READY
ar0: disk0 READY (master) using ad4 at ata2-master
ar0: disk1 READY (mirror) using ad6 at ata3-master
<snip>
WARNING: /usr was not properly dismounted
WARNING: /var was not properly dismounted
WARNING: R/W mount of /mnt/journaled denied.  Filesystem is not clean - run 
fsck

Only /mnt/journaled (ad10s1.journal) is gjournaled. Why doesn't fsck, which is 
running in background mode by now, check my /mnt/journaled and tag it clean? 
I have to manually fsck /dev/ad10s1.journal and manually remount it. This is 
a no-go because I want my system to be able to run without the helps of us, 
bipeds even in the event of a crash :). /usr and /var where fsck'ed in 
background as expected.

Therefore, is it possible to make a crash recovery with gjournal without the 
need of humains? Can I boot from a crash, with background_fsck="NO" and still 
mount the journaled FS?

2. Since my new server will require a fresh installation, can I set up my 
gjournal slices from within sysinstall by choosing "Custom NewFS" and putting 
the -J option in there? Will that load the gjournal module? What is the 
correct way to implement gjournal (and if possible with gmirror) from a fresh 
start?

3. From gjournal(8) man page: "It is not recommended to use gjournal for small 
file systems (e.g.: only few gigabytes big)." How much is a "few"? Is it < 
10gb? <50gb? I intend to use gjournal on /var (10gb), /usr (100gb), /home 
(1tb) and some misc mounts. (~25-100gb).

4. I'm thinking of using gmirror instead of my MB's onboard raid. I found from 
previous posts that I can mount async, disable soft-updates and that for 
simplicity it would be better to mirror the whole drive instead of slices 
(which is what I'm intending to do). Anything else I could use/know about 
using gmirror and gjournal? 

Thank you VERY MUCH for your help.

Nicolas.
-- 
FreeBSD 7.0-CURRENT #18: Sun Mar 25 16:03:50 EDT 2007     
nicblais at clk01a:/usr/obj/usr/src/sys/CLK01A 
PGP? : http://plaintext.clkroot.net/security/nb_root.asc
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