A Raid array of Disk images volumes

[king.pa]

Hi,

I'm looking for a way to get blank disk images files which could be used as a raid array with windows dynamic disk feature.

here's my situation :

I've got 4 disks in my PC, with multiple partitions. I'm using 4 wow at a time with a E6600 @ 3 Ghz and 2 GB of Ram.. all of the WOWs are on the same disk using the symbolik link feature in vista (i've tested to have 1 wow per disk, but the windows disk management is not as smooth as it could be encountered with mac os x (on the same hardware) and it's pretty much the same pain to get data loaded from different disks than all datas on the same drive.. anyway
in town.. this is killing my PC hard drive... and I can't even walk through Stormwind without loosing the follow of my clones two or three times ...
I've made a test yesterday .. it took me 9 minutes to go from a random location to satrahh then to exodar with my 4 girls using the return stone!

So...
On my mac, I can create as much as Disk images (.dmg) as I want ... I can also make a raid1 array with the volumes from the separate mounted disk images.
I want to do the same with my PC on vista ... I've tested several shareware and software .. but none of them can create empty disk images as it can be easyly done on Mac

I would like to get four disk images (writable or not.. I just want to get the Data folder on it) and have four separate disk image files around my disks, create a dynamic array with the four mounted volumes then use the symbolik link feature with the data folder on it... It have to be possible ... making a disk image from a folder and split disk image file into four different files ...

Can you help me with this idea ? It can be made easyly with four average 2 Gb SD Card and four USB2 card Readers... but I don't want to buy anything for the moment ...

thanks for your help guys
(BTW excuse my poor english, and the mistakes in my spelling)

[Crucial]

Consider adding more RAM first? 2gb + vista and 4 wows + shattrath = lag

[king.pa]

I've added a Gig of ram today.. I'll check if it's faster than two gig.... but anyway ... the "raid of disk image saved on multiple hard drives" feature could be a nice tweak to disk performance ...
[EDIT] new ram is already toasted .. can't test the 3 gig boost ....

[king.pa]

UP

nobody's interested in such a feature...

a simili raid for the data folder ... it could be a nice tweak to boost I/O of game data loading ...

[Sarduci]

You've tweaked my interest, but I have no idea what you're actually trying to accomplish. It seems like you're adding a ton of overhead work for a performance loss.

If you only have 1 physical disk, you're splitting the I/O reads and writes over 1 spindle. If you have 3 disks in a raid setup, the you can split the O/I over 3 spindles. 50 virtual disk sitting on one physical drive still only have 1 spindle to do I/O over.

[king.pa]

Yup, ur right ...

But imagine you can create a non physical array of disk images all around your disks ...

this tweaking is worthless on a sigle drive, or partition using the same hardware drive .. no I meant to use this feature on different physical drives ... without the need to reformat each drive, backup data etc etc

and I don't have any room left in my tower to put two other old 20gig drives to make a 40 Gig raid1 array

four disks .. four times the I/O outpout ... just for the data directory ... I don't really know how to explain my thoughts, but it could be huge !!!!



btw.. I've added the gig of ram we talk earlyer ... and great improvement of loading times, and smoothness of the game .. no more half-hour to go a town to another...

[Sarduci]

RAID 5 has faster than single drive read rates, slower than single drive write rates. RAID 0 has faster than single drive write rate, slower than single drive read rates. Raid 1 is slower read and write rates than single drive speeds.

Whatever your doing, keep the above in mind.

[wowphreak]

the performance gain yeh will get outta having 4 gigs of memory gonna be an order of an magnitude greater then trying to tweak yer hard drives to hell and back

Vista needs 2 gigs of memory to not hit the hard drive, each instance of wow needs 200+ megs of ram being in a major city it'll be higher, never actually checked how much.

When yeh only got 2 gigs what happens is vista loads then start paging thing it doesn't need immediately, to the hard drive

Only times hard drive speed/access will make a difference is when yer switching zones or getting into/out an instance.

[Djarid]

RAID 5 has faster than single drive read rates, slower than single drive write rates. RAID 0 has faster than single drive write rate, slower than single drive read rates. Raid 1 is slower read and write rates than single drive speeds.

Whatever your doing, keep the above in mind.

That is a lot of generalisation going on right there ;)

Ok for this audience you are likely correct but with decent hardware raid cards / cache etc it is a lot less clear cut. A single disk can't utilise all the bandwidth available on a SATA 3Gb/s or even SCSI 320 bus, given a decent RAID controller you can get performance that exceeds a single disk performance on both read and write on both RAID 1 and RAID5 and if you can afford RAID0 or 10 you will see significant benefits.

NOTE: Afford in that last sentence is for data integrity in RAID0 and hardware cost in RAID10

[Sarduci]

RAID 5 has faster than single drive read rates, slower than single drive write rates. RAID 0 has faster than single drive write rate, slower than single drive read rates. Raid 1 is slower read and write rates than single drive speeds.

Whatever your doing, keep the above in mind.

That is a lot of generalisation going on right there

Ok for this audience you are likely correct but with decent hardware raid cards / cache etc it is a lot less clear cut. A single disk can't utilise all the bandwidth available on a SATA 3Gb/s or even SCSI 320 bus, given a decent RAID controller you can get performance that exceeds a single disk performance on both read and write on both RAID 1 and RAID5 and if you can afford RAID0 or 10 you will see significant benefits.

NOTE: Afford in that last sentence is for data integrity in RAID0 and hardware cost in RAID10

Quite the generalization there yourself.. [img]../forum/images/smilies/rolleyes.png[/img]

May I point you to this to give you a better overview of which you speak.
http://en.wikipedia.org/wiki/RAID

I have hundreds of block level access devices (SAN and iSCSI SAN) running in just about any configuration you can think of running a variety of fiber, SCSI, PATA and SATA solutions in single hardware and mixed-in-chassis drive environments at over 500 different customer locations. 0, 1, 5, 15, 10, 01 (yes, 10 and 01 are different) 55, 6, 2, and 3. The only one I currently do not have is RAID4, which is by far too slow for use. By understanding on what end the bulk of the XOR parity calculations are done on your different RAID sets, you can fine tune your performance penalty to be on your least used data manipulation, either hardware or software.

The smaller databases we work with are several TB in size with several million transactions per day posted to it and hundreds of millions of transactions being pulled from it in a variety of tier 1 banking and fortune 100 companies. Using that as a baseline, we use up to 4 redundant RAID controllers in write through configurations which have shared interconnects for internally load balancing the I/O from the host controllers with up to 4 channels of 4GB fiber from a single host. That being said, I can easily saturate a small drive set with data requests (read or write), and using the above guidelines under that condition you will find the above statements to be accurate.

We are actually actively looking for a new SAN vendor because some of our larger customers generate somewhere around 160GB/day of new data in beta non-production environments. At the suggested data input rates we have, they'd need to buy another one of the biggest SANs we sell every month. Mind you, the biggest drive we can currently get is 1TB SATA 2.5" drives to hit the density of rack space required.


And back to the point of this thread, running virtual disk drives on top 1 physical drive is a bad thing. [img]../forum/images/smilies/thumbsup.png[/img]