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Array Configuration!!

Occasional Contributor

Array Configuration!!

The question i have is about Array Configuration. Which of the below two configuration would give a faster disk-to-disk write speed..
Single Array Configuration (w/Raid<>5) or
Two or more Array Configuration (w/Raid<>5).

Looking forward to your replies

meredith shaebanyan
Occasional Advisor

Re: Array Configuration!!

Single Arrag (w/Raid 5) would give you faster single-process access to the disk, since your data is being striped across more disks (more concurrent IO).

Two or more array's would give you better performance if you have multiple processes trying to do IO as both array's can be written to concurrently.

For example, in the database world it is standard practice to separate out Logs and Data on separate logical disks. This allows both to be written to concurrently, increasing IO throughput.

Meredith Shaebanyan
Occasional Contributor

Re: Array Configuration!!

Thank you for the response.
As far as writing speed is concerned, i dont have any fond memories with Raid5. After years of working with Raid5 on our Database server, we finally saw great improvement when we started using Raid1+0.
We are using VMWare on our servers and it was found that disks configured with Raid5 took double the time (than Raid10) to copy files from the Host machine to the Guest VM. The guest VMs will function as my backup or hot spares for my production server. The daily/hourly backups would come and sit on the Host machine and will be transfered to the guest VM. The transfer (or copying) performance was better on a similar server with Raid10 than the one on Raid5. So having that confirmed, i just need to decide if to keep both the host and guest on the same array configured with Raid10 or have two arrays of Raid10 housing the host and the guest. Dont forget..there is going to be a lot of writing involved. The server is a ML 370 DualCore Dual Processor G5 with 10Gigs of Ram and 9/146gb disks.

Joshua Small_2
Valued Contributor

Re: Array Configuration!!

Two RAID 1 arrays are essentially the same as one big RAID 10 array.

Be aware that the actual performance difference with any RAID configuration is nowhere near the difference you will gain by purchasing an appropriate cache module for your RAID card.