SSD / HDD Setup Structure

Computer is a Dell Precision M6500...

I've currently got my hard drives set up in RAID0 (2x 500GB 7200's) and I'm not really pleased with the drive read / write speeds during normal use. Access time makes the drives no faster than using them W/O RAID it seems, and I'm really increasing my risk of data loss, so I'm going to get rid of the RAID and add a SSD as the primary.

I've got a 120GB Intel X25, and will be keeping the two hard drives as well (replace the DVD drive with an internal HDD). So here's what I was thinking on the file structure setup; any ideas to make it better?

SSD:
OS, Program Files, and User's App / Program Data

HDD1:
Music, Docs, Video, and Page File (I don't expect it to be used much w/ 12GB RAM)

HDD2:
Virtual Machines, Source files I work with

Is there anything I'm missing or should be moved to be better in this system?

 

You may consider RAID 1 for the two HDD as read from RAID 1 is no slower than RAID 0(should be even faster) and it gives you the redundency. Should benefit the page file a bit too(as microsoft's data shows that page file is heavily read skewed).

Of course, you give up half the size which I am not sure if it is important.

 

Not sure where you're getting your info from. RAID0 almost doubles sequential read and write speeds and is much better for transferring files, though there is an increase in risk due to drive failure. The SSD will definitely make things snappier as the access time and random R/W speeds are exponentially better. Your setup seems fine for your purposes.

 

@chimpanzee: This is all incorrect. RAID 1 is a mirrored configuration, while RAID 0 is a striped, shared workload configuration. RAID 0 increases speed (relative to a single HDD) while RAID 1 is redundant (and equal in speed to a single HDD at best).

OP: Just an FYI; I have recently upgraded to a single SSD (as in I only have 1 HDD bay). I do everything (except torrent) on it. I have a page file (necessary with 4GB RAM and SC2's retarded memory leak), but turned off superfetch/prefetch. With this setup I only write ~2GB to the drive a day (10% of Intel's specifications). I would highly advocate an SSD, and even putting the PF on it.

 

Dont bother with RAID1 redundancy for storage drives. It is not a backup solution.

You will be better off dedicating a HD for backups. eg. Use the Optical bay HD as the backup drive, so you can just take it out and keep it somewhere safe.

Splitting up your data on 2 drives is good if you have an external backup of it. Otherwise you run the risk of losing half of your data if a drive fails, or even all if both simultaneously fail.

 

RAID 1 is redundant which is why it can read just as fast(sometime faster) than RAID 0. A smart RAID controller would know that either drive would give you the exact same info so it can parallelize the read.

Which one does that unfortunately depends on specific implementation.

This link talked about it

Does RAID 1 actually increase read speed? - NAS-RAID-Technologies - Storage

Let me clarify again, RAID 1 cannot improve write performance but can improve read performance(which theoretically can be even faster than RAID 0).

This benchmark was done back in 2005. Pay attention to the 'IO Meter - Web Server' graph which is a typical READ heavy benchmark

http://techreport.com/articles.x/8059/7

 

Yes, I had to correct you because you didn't specify that it was only the READ that could conceivably be faster. And depending on the implementation and RAID BIOS/drivers/hardware, the read may never even be faster. Some systems required redundant retrieval from both disks at each read (resulting in slower reads than a single HDD on average).

 

This was what I said :

You may consider RAID 1 for the two HDD as read from RAID 1 is no slower than RAID 0(should be even faster)

Also, the OP seems to be running Intel based notebook so it is highly likely that he was using Intel's driver for the RAID configuration which was the driver the 2005 link was testing. Of course, may be newer Matrix driver no longer does that.

Going a bit off topic, why would a RAID 1 implementation need redundant retreval from both disk ? That seems to break what RAID 1 is for. If the read doesn't agree, then what ? returning read error ?

and this one from Microsoft in their SQL Server 2005 info

http://msdn.microsoft.com/en-us/library/ms190764(SQL.90).aspx

RAID 1 provides fault tolerance and generally improves read performance but may degrade write performance.

 

Exactly. In certain RAID 1 configs, redundancy is checked at every read, meaning that it's necessary for both disks to be read. This is common in server arrays AFAIK.

 

I am a bit lost of what you meant by 'exactly'.

This has gone way off topic now and I think we better stop here.

 

Thanks for the responses!

@chimpanzee: I thought about doing RAID1, but I do use Acronis to back up and the only data I need to back up are the documents and files for websites I'm currently working with, so I can easily keep multiple backups on my external hard drives. I don't care so much about the OS and program files since they're just a matter of re-installing. The extra disc space isn't 100% necessary, but I do have enough that it'll start degrading performance since the disc will get fuller.

@sgogeta4: The drive throughput is great with large files. Unfortunately, with the drive access latency, it's not a noticeable difference booting or launching applications relative to a single drive configuration. Throughput was hitting very high numbers when benchmarking, but the actual real-world performance wasn't impressive.

I ended up setting up the drives as I initially proposed, and boot times are cut (after post) to about 1/4 the time it was taking with my RAID0, and the system is much more responsive on application launches overall. If only I had the money to stripe raid 3 SSD's...

 

Everything seems to be working great so far, but out of curiousity, does anyone know how the Windows Experience Index is calculated? I'm showing a 5.9 under hard drive, and I'm getting transfers > 100MB/sec according to the performance monitor. My i7 processor is only showing 6.2, which also seems a bit low. Performance seems to be on par with expectations.

 

I know that with a (single) mechanical HDD, WEI is capped at 5.9. Period. So maybe your RAIDed HDDs are limiting the WEI of your system?

 

Yes RAID0 will instantly double your scores in benchmarks but actual real world performance, it only equates to about 5-15% increase for the large majority of tasks. The performance gain compared to a single HDD is hardly worth the doubled risk of complete data loss.

Using an SSD as a OS drive is a better solution than RAID0. Quick latency, fast random read & writes and just fast at everything.

Ignore the WEI scores, it isnt a proper benchmark.