RAID suggestions required plz

[tinku]

Hello,
sorry, but i'm really really poor at this. i'm trying to learn, so plz help me out.
I intend to do the following with my box:
set up 3 virtual pcs, one with windows 2000, one with windows 2003 and one with solaris 10 and run web servers and application servers on all of them. i want them to talk to each other like independent servers do. each will have its own virtual ip number and the whole environment should simulate an enterprise environment. basically, i'm setting up web servers, application servers, ldap servers, database servers at the software level

here's the hardware i have:
1. amd sempron 3000 1.8Ghz with 1600 (or 1800?) fsb (64-bit processor)
2. 2 gb ram
3. 2xsata hdds @ 80gb each. 7200 rpm
4. built-in lan, audio, video, etc. - if you need any other info, plz let me know.

i could not afford to get the 10k rpm 80gb hdd. so, i got 2x80gb hdds at 7200rpm. now since i want to run 3 virtual pcs, i want the processor to be really fast (i have extra fans in place). and i want a raid configuration that'll help me achieve this goal...so, would i need a raid0 configuration?
i'll connect to my box from work and need it to run smoothly and need it to run fast!

since i'll be running all my examples on a virtual pc, i'm not worried about my box failing. i just want it to be fast fast fast. :bounce:

so, please give me suggestions as to how to do this with this hardware. i really can't afford anything more than this now.

also, some questions:
1. i have a 160gb hdd - usb external. will i be able to use this once i configure the 2 sata hdds in raid? i wanna be able to connect this to the box and go to work, but i wanna primarily work with only the 2 sata hdds configured in raid. i'd like to access this external 160gb hdd only for creating backups. will i be able to do this?

2. most of my files are 4-6 mb in size, although sometimes, i'll run in to the 15mb files. what strip size should i use? i think my box gives the max option of 128kb (i think i ended up getting a cheap mobo)

it could be great if you guys could give me a few suggestions. thanks, everyone.

-tinku
ps: if you think the hardware configuration is downright not good, then feel free to suggest a configuration on your own. my budget is 600-700. maybe i could return this and get a new box. :unch:

 

[Blakhart]

Hi
Well, as to raid arrays and their effect upon performance, if you really need random scattered small file access rather than max transfer of large files as in a vid editing system, using the drives independantly on each channel, non raided may be best. See, raid0 really is better for huge file work rather than what you seem to want to do. There's also the greater risk of data loss because raid0 is not redundant.
There are ways to get a raid0 array to perform better with small files, and that's to set a stripe size between 64 and 128 or more. See, lower stripe size favors large file performance while greater stripe size favors small files. See here for more on raid arrays: http://www.pcguide.com/ref/hdd/perf/raid/concepts/perfStripe-c.html

Now if you wanted to forgo the raid array, having one drive for the os/seldom used data/backups and the other drive for the apps/utes/etc will allow simultaneous access to each drive, enhancing performance.
In this case one could set a pagefile on each drive to increase paging performance as well.

Some thoughts for you.

 

[tdeg]

I agree with you.

RAID may not be the best option for you in the instant.

 

[tinku]

hi
thanks for your views. i tried setting up raid-0 and had a major headache. :knock: i've just never done it before. but i wanna see how much better it will turn out to be. hopefully i'll be done with the configuration tonight.

i have been going thru' my mobo's manual, but i have a quick question.

1. is configuring the raid in the bios and then installing OS is the same as "configuring raid-0 at hardware level"? i had to press f6 and install 3rd-party drivers during the OS installation. now i'm in the middle of installing the OS.

if that's not the same as "configuring raid at the hardware level", then what is? i don't want to deal with it at the s/w level as i want to use my whole processor & ram power only for running my virtual pcs.

2. any good sites out there that might help me tweak my windows xp pro sp2 to a bare minimum so as to make complete use of my processor & ram just for virtual pcs?

Thanks again guys! :grinthumb
-tinku

 

[Blakhart]

Hi
Yeah when you use bios to set the raid parameters you're at the hardware level. Wether it's a card or on the mobo.

As far as tweaks go, there are a few guides to disabling unneeded services in xp that can be found on the net. Some of your apps may depend on some services so you will have to test each change. One thing I would do is to right click my computer/properties/advanced/performance settings, and check "adjust for best performance." Then go into advanced under the same performance options tab and set processor sheduling to background services. This will ensure that each app gets equal cpu timeslices, and you should note smoother performance. In the same area is a button to select large system cache. This is not really a good thing to use since if an app needs the mem that large system cache is holding, the system will not give the mem up. It will be held and the app will likely error out.

 

[tinku]

Hi again, :wave:
i made the changes you suggested..also i'm going through a coupla sites that will help me bring my xp-settings down to a bare minimum and not mess up with the performance.

i think i have raid-0 set up properly now. "my computer" shows 148gb (which is correct, because i had 2 80gb sata hdds). but how do i know that it's raid-0 configured? any testing tools out there for me to check this out? also, i'm glad to know that i did it at the hardware level. i didn't have to set anything at the s/w level, but again, that keeps bugging me because i have no way to test the configuration.

i am also able to use my external usb hdd nicely. so that's cool. most of the programs i need are on that external hdd. plus, i'd be using that for backups.

please give me some input on that tool. i'll download that tool, do some performance testing with raid-0 config and w/o the raid-o config and then use once of them accordingly.
thanks, again!
-tinku
210am! whoa :zzz:

 

[Blakhart]

Hi
If you have two physical drives and the system shows the sum of their capacity as one volume, you're striped. That means raid0 in a 2 drive array. Really we should call it aid0 as there's no redundancy...
Speaking of redundancy, in raid0 if one drive loses data or just farts the whole volume is toast, there's no recovery possible, so you better back up whenever you can or you'll regret it. There are other raid modes for two drives as if each were the only drive installed, all data is written and read to/from both drives simultaneously. This assures redundancy as if one drive dies, the other has all data copied. I dunno if your raid controller allows functions other than raid0, best read up on what it allows.

I would use a nifty app called iometer by Intel. This will show you what the array will do as far as webserving and other server duties go. I also like the HDSPEED disk speed test by George, found here at : http://www.georgebreese.com/net/software/#HDSPEED

Have fun!

 

[tinku]

hi again!
i'm gonna try those downloads this evening. thanks! i'll run

meanwhile, i wanted to ask you about something a co-worker suggested. he asked me to expect a lot of hdd failures with striping, too. so he suggested the following (but then ran off w/o telling me how to implement it):

1. 2 80gb sata hdds @ 7200rpm
2. do a combination of striping and mirroring (but not really raid0+1 - as that requires at least 4 hdds or something?)
3. 10 gb on each hdd dedicated to OS, tweaks and basic installs (virtual pcs, firewall, etc). and these 2x10gb should mirror each other (raid-1 config?)
4. then the remaining space, ie, 140gb could be used for only striping.

A. is this setup possible?
B. if so, how the heck should i go about it? cuz my head is spinning.

my mobo setup gives me the following options while setting up raid
1. mirror 2. striping 3. mirror+striping 4. an option that simply combines all hdds of various sizes to use like normal hdd (we aren't concerned with this, i think).

i tried #1 last night; my computer could detect 2 hdd @ 74.x gb and both drives had the same contents ("Documents and Settings", "Program Files", "Windows", etc). to check if it's mirroring properly, i created a new folder in C:, but it didn't show up in D:. I'm sure I'm missing some step for those 2 drives to synch each other. So, what is that step?
Once i finish that step, will writing to D: be mirrored in C:? We don't really need to do this, because right now, i'm not using that raid-1 config.

i went back and tried #2 again, and that's where i am right now.

Anywho. any thoughts anyone can provide will be beneficial. hopefully i'll be able to set this thing up by this weekend, cuz i need to work on things seriously by next monday!
thanks again for your replies!

 

[tinku]

i'll run them on my laptops for kicks, is what i wanted to say...lost my head there for a second. :giddy:

 

[Blakhart]

Hi
If an array is mirrored and the data isn't shown identicaly on each drive then you're not mirrored. Simple as that, as the "reflection" from a mirror should be identical to the source of the "image." Dunno what's going on here with the mirrored bit. By the way, the mode where all drives show up as one large drive, non striped, is called JBoD. Just a Bunch of Disks...

The thing to partitioning a drive or array is that you always reduce performance by so doing. Drives/arrays should have single partitions for best performance, well, within reason, and simply to use folders to divvy up data/apps/whatever. Much faster as the heads don't have to cross a partition, wich adds latency to seeks and so on. Xp is more efficient in general when drives/arrays have a single partition.

As to this:
1. 2 80gb sata hdds @ 7200rpm
2. do a combination of striping and mirroring (but not really raid0+1 - as that requires at least 4 hdds or something?)
3. 10 gb on each hdd dedicated to OS, tweaks and basic installs (virtual pcs, firewall, etc). and these 2x10gb should mirror each other (raid-1 config?)
4. then the remaining space, ie, 140gb could be used for only striping.

That's a complicated order. More complexity means more risk for failure, and you really should get assistance from one who has created and used this type of array. I have none as you can tell! As well, the raid controller must pass everything you want to do, array and partition strategy-wise. Plus, if the array(s) isn't/aren't done in hardware and not software, I seriously doubt the reliability of the system.

Sorry I'm not more help here.

 

[tinku]

hey :wave:
you're right. i'm not sure if i should be doing it either. have been thinking about it all day. can't try it until i get home.

i'm gonna stick with raid-0 and since my external hdd works fine with it, i'll do periodical backups.

also, i'm gonna run those tests you asked me to tonight, so that'll give me an idea if i should even worry about other raid configs. the whole point was to get maximum hdd reading/writing capacity. if the OS fails, let it. at least i'll know how good it is.

thanks for your input. this was a healthy exercise for me.
-tinku :giddy: