[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Web server Partitions - me

On Fri, 19 Dec 2003, Lucas Albers wrote:

> >
> > hi ya andrew
> > raid can break due to:
> > 	- (1) disk failures
> > 	- the silly system takes forever ( dayz ) to resync itself
> > 	- too many disks failures renders the entire raid useless
> > 	or the system can be on a non-raided disk and raid5 for data only
> > 		- have an 2nd system disk for backup and go live by
> > 		simply changing its ip# and hostname
> > there is no point to raiding /tmp ...
> > 	- if the system dies ... all temp data in /tmp wont matter
> >
> > 	- swap is already "semi-raided" by the kernel
> > 	and if it dies... swap data is generally useless anyway
> >
> > c ya
> > alvin
> I was thinking about this idea, so /tmp is on raid. Now temp dies, and you
> reboot, and now apache won't start? 

if /tmp is a separate partition and it cannot mount it during bootup,
nothing will work right if the app depends on /tmp, not just apache

/tmp will get into trouble if you improperly powered off

> I've decided to start making my raid
> syncs into smaller sizes, so they can resync back faster. 

the size of the "raid" has NOTHING to do with "resync" faster in general

the number of files and data that have to be sync between the
degraded raid and the newly inserted disk does make a difference
	- faster oyu notice a dead/dying raid disk and replace
	it implies that there is less time wasted in degraded raid mode
	and minimizes data loss if another disk dies

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

huh ?? curious .. what and how ??

sync is always required for nfs or raid or whatever ther apps that like
to have "sync" specified 

nothing to do with "volumes" ??

> it's always one disk or partition
> consistently pukes out, Why is always the same disk/partition?

what disk/partition is puking??
	how is it puking ???

> I think I will just make a raid 0 partition for temp, as you mentioned, if
> the disk dies all the partitions are dead.

for clarification, i did NOT mention to use raid0 for temp ( /tmp )
	- there is also zero point in making /tmp raid0
	unless one is doing say some huge GB-sized app that requires
	lots of GB-sized temp data in /tmp

- 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 )
- differences in raid

imho ...  a properly partitioned and installed linux, for my
reasons/purposes is:
	/	256MB
	/tmp	256MB
	/var	512MB
	/usr	4096MB
	swap	512MB
	/opt	rest of disk ( aka /home )

	-- if you need more disk space for whatever, than move that
	directory to "user area" ( /home ) and keep the system clean so
	you can fix or restore the system whenver needed in a few minutes

other partiton schmes

> Have you noticed any syn speed difference with differnt kernels?

nope ... havent tested for it either

> In related news I finally got debian to boot from a software raid
> partition as root.
> Start to finish..yippee.


c ya

Reply to: