outer diameter hard disk and partitioning

[studio.dmd]

Hello, this is my first post!

I need an advice.
Here we need to install an external eSATA-II 2bay raid system, with two sata-ii hard disks formatted in RAID0, and use it as a virtual memory/scratch disk for photoshop (we work with huge graphic files, also 5-10 GB of opened size, and we can't wait the classic virtual memory shared with the other apps. virtual memory, the OS v.m., the OS etc... on the same disk).

I read a lot about the outer space of the hard disk, and that when the disk is empty the data will go faster. For example a two disks raid 0 system, with 90% of empty space can erogate up to 140-150 MB/sec. speed (about 70 MB per disk), but when it is about 50-80% full the speed decreases to about 50 MB/sec.

So when I format a new hard disk I'm sure that I'm using the faster zones.
I read that we can make two partitions: for example in a 320 GB hard disk, we can do a 30 GB faster partition and a 290 GB data partition. We should put the data in the bigger partition, and the first partition will remain always faster, even if the hard disk will be filled, because the partition will use the outer faster zones of the disk, while the data will occupy the slower zones.

So we'll format the drive (or the two-drives striped in RAID 0) creating a first 30 GB partition and a second 290 GB partition.

So this is my question: how can we be sure that the first partition is using the faster zones?

When we format a disk in a single 100% partition we know that the data will be automatically stored in the faster zones before; than as we will fill the disk, the data will be stored towards the slower zones.

But is this the same while partitioning (pre formatting) the disk? Will the first partition automatically occupy the faster zones too?

Thank you.

 

[P5-133XL]

Use HDTach to test/benchmark the specific drive/Controller combo. Now mind you, as far as I know all drives and controllers store from the outside in ...

 

[ddrueding]

I too thought it was outside-in.

Seagate Tech Paper (PDF)

Other IT professionals choose to increase their 10K-RPM drives’ performance by storing data only on the outer diameter of the disc,
a practice referred to as short-stroking (or destroking). Short-stroking a drive reduces the distance the actuator must move to access
the data, and thus improves disc seek time. Of course, such an approach greatly reduces effective disc capacity, escalating the
cost/GB of the drive. (For example, a 10K-RPM 146GB drive short-stroked to yield 73GB capacity costs significantly more per GB
than a 10K-RPM 73GB drive.)

I've done it in the past; building a large array of drives, creating a RAID-0 with the first 10GB or so of each. It is pretty quick, but SSDs are quicker.

 

[studio.dmd]

which method?

I've done it in the past; building a large array of drives, creating a RAID-0 with the first 10GB or so of each. It is pretty quick, but SSDs are quicker.

And how did you do?
Did you first partitioned the drives using only the first 10GB for each and then formatted them in a RAID0 volume of 10 GB x numbers of drives, or did you partitioned and formatted them using 100% of space, than created the RAID0 volume and then divided the whole RAID0 volume (using 100% of disk space of each drive) in two partitions: the first of the size of 10 GB x numbers of drive, and the second partition unused?

Thanks a lots.

 

[ddrueding]

I created the RAID-0 array, then partitioned the first 50GB (10GB per drive) for the OS. Of course, you should never put important data on a RAID-0, so the rest of the drives are not particularly useful. IIRC, Linux now supports software RAID that allows the first chunk to be RAID-0 and the rest to be RAID-5, but I know nothing about that.

 

[ddrueding]

Keep in mind your needs will be better served with one of these.

 

[studio.dmd]

I created the RAID-0 array, then partitioned the first 50GB

but is it possible to create (format) a RAID-0 array without partition the disks, or should I partition each disk first, then format all them in RAID-0 and then re-partition the whole RAID-0 volume?

About Solid State Disk, I know that they have about 20-40 MB/sec. vs 100-150 MB/sec of two disks in RAID0, so with huge files in photoshop I think the waiting will be very long...

 

[Bozo]

Create the RAID 0 array using the RAID controllers setup routine. Then create the first partition to what ever size you think is appropriate for your needs. It will be on the outer cylinders of all the hard disk.
Then create your storage area on the remaining hard drive space. It will be on the inner cylinders of the hard drives.

Bozo :joker:

 

[studio.dmd]

I understood

Thanks a lot to all you.
Bye.