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Re: Web server Partitions - me



hi ya lucas

On Fri, 19 Dec 2003, Lucas Albers wrote:

> What I meant, was if it is a partition size the resync will occur faster
> then if it is a giant partition size.

makes no difference ... "100GB of data to sync" is 100GB of data 
no matter how small ..

but if you spread 100GB to 20GB each on 5 disks ..
that will be 1/5 the time to resync the 100GB of data
	( the whole point of raid5 )

but it will be say 2x slower to write the 100GB (20GB) of data to 5 disks

> I think I'm just going to put spare backup disk in the system.

usually simpler to use 1 disk for spare.. as long as everythng
fit and you dont have to worry about any config errors

> >> I've found that some volumes just break sync,
> >
...

> I have a raid 5 partiton hde,hdf,hdg,hdh.
> And sometimes hde gets confused and I have to raidhotadd then raidhotadd.
> Happens every couple of weeks, always the same partition that decides to
> go on vacation from the raid set.

sounds like hd3 is a dying disk
	- do you have "SMART" turned on it ??
	- do you check the cables for it ??? make sure it is ata-100
	cables instead of the cheap/fat ata-33 cables

you should NOT have to do that ... raidhotremove/raidhotadd...

> >
> > - in general, i do not recommend raid0 ( stripping ), unless you want:
> > 	- makes a bunch of smaller disks look like one  bigger disk
> > 	- allows you to read data 2x faster if you "mirror it"
> > 		( raid0 across  md0 and md1
> > 		( where both mdo0 and md1 is a mirror of md0 )
> >
> Good information, to much effort to stripe and mirror, I'll just stay with
> raid1 or raid5.

yup... and lots of hidden problkems with mirror too ...
	- erase importantfile.txt  and its almost instantly gone from
	the mirror ..ooops
 
> this is what I have used;
> > 	/	1G
>         /boot   100M

> > 	swap	512MB
> > 	/opt	rest of disk ( aka /home )
> 
> Should make seperate /tmp /var partitions on my webserver, thanks for
> reminding me.

/tmp is 100x ( 1000x ) more important than having /boot 

> > other partiton schmes
> > 	http://www.Linux-1U.net/Partitions
> Will take a look at it, too much info...my belly is full.

raiding on top of all that will overflow the full tummy :-0

> Anecdotally I noticed that optimized an athlon or similar 2.4.22 kernels
> on my systems get 14meg, and stock kernels get slower on syncs.

yes... you should see faster performance on tuned kernels ...

and if you wanna tune it more ..
	http://www.Linux-1U.net/Tuning

- there's some pretty ( partition & raid ) pics at the bottom too

c ya
alvin



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