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Re: (Large) Logical Volume Management

Samuele Catusian wrote:

Hail folks.

I've to set up an ~1TB SAN on our network. We're thinking about recycling
an existing server with an HP SmartArray 641 RAID Controller and expanding it with another SA641 controller and some more disks, or directly purchasing an HP fiber Storage Area Network. In both cases I'll have to create a unique logical volume, and I'm wondering which logical volume manager to use. The machine will be a production system, it must be stable and reliable, fairly fast in disks 
access, and I'd like to run a 2.6 kernel on it. Lately I've used EVMS on
some small systems and it left me well impressed; is it sufficiently
mature and stable to be used with good results on such a system? Are there other _valid_ alternatives? 

And, of course, I'll have to use a journaled filesystem on top of the
LVM. The average size of the files is about hundreds KiloBytes, seldom reaching the whole MB. The directories hierarchy will be fixed and highly structured, organized like this: 

	/Year/
	  |__Month/
	      |__Day/
	          |__Hour/
		      |__Minute/
The number of stored files will be about 1,5 millions, and the estimated access rate will remain lower than 1,000 access/sec, with 30% write and 70% read. I've played for so long with ext3 and XFS filesystems, but both seems to have efficiency problems with setups like this. May someone give me some advices about the filesystem choice? Could ReiserFS be a valid solution? Should I consider other filesystems?
Thanks to all. Greetings.
I've got no experience with such big and demanding setups, but I am familiar with smaller ones tough, 150 - 400 G raid arrays with everything from oracle databases to web and email servers for some ~12k users.
I've been using reiserfs for all production servers for several years now, and it is rock solid, and for a bigger setup I wouldn't use anything else (heck, for any other setup!). For most of the arrays, I use LVM v1, and it's also very solid, although the nightly snapshots sometimes (~ 2 out of 30) don't get made correctly, so we may skip the backup of such day.
All of this with kernel 2.4.2x. I would prefer to let the dust settle a bit over 2.6 before trying it in a production box.
Sometime ago, I experimented with lvm v2 and evm in a testing environment, but concluded to use lvm v1 for it's stability record, and have been quite happy with the lack of surprises. Probably at this point evm has matured enough to give it a try again. 

 Just my 0.02


José
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