Question about extraction speed from RAID-0

[sashok07]

So... a customer brought 6TB WD (RAID-0) with one of the two hard drives failed. I replaced the heads and reimaged the drive through PC3K. Tested the second drive no read or write problems what so ever (both drives are 100% now). I reconstructed the array via UFS and R-Studio (successfully, all files are there and are non corrupt).

HERE IS THE PROBLEM, the client has 4TB worth of data and its copying/extracting at a snails pace. R-Studio reports it will take 8 days to copy.. I tried UFS (overnight) and it only copied 250GB over 8 hours..

Customer files consist primarily at large (few GBs a piece video files) so there is no reason for such slow down, I am copying to the data to another directly hooked up SATA drive which is also 100% functional. I tried multiple computers and sata controllers with no luck.

Any suggestions?

[michael chiklis]

Have you check Re-Lo list (mod 32)?
If so then you have to clear it in pc3000.
Check it!

If you do head swap and you have pc3000 very likely you are DR pro so i think you already check g-list, right?
Maybe you forgot to check Re-Lo...

P.S.
You can also try to clone the second drive in DE with very low timing on loss of readiness, this should help to read sector faster while cloning

Last edited by michael chiklis on August 7th, 2014, 9:59, edited 1 time in total.

[lcoughey]

Are you working from a known good clone of both drives?

[hhddrec]

The best un those cases es to clone allí drives and work with known good working hdd.
This is the best way. Un fact you can test if the other drives ore ingood condition por not.

[sashok07]

This has nothing to do with PC3K, as I said the failed drive has already been cloned (onto a brand new hard drive), the second drive is 100% good (I thoroughly tested it). I would never risk using original drive unless I was 100% that it was 100% functional and it most definitely is.

I had this problem with another RAID before (G-Tech Mini); obviously totally different drives, the only thing in common was that they both where RAID-0 at 512 bytes (1 sector) block size.

I guess if both drives are in working order there isn't much to be done huh.. patience is not one of my virtues (nor my clients for that matter). Sigh

[michael chiklis]

I misunderstood, sorry i don't know how to help on this

[pcimage]

Last single-sector stripe raid I recovered was also horrifically slow, took days.

[Dmitri]

a customer brought 6TB WD (RAID-0) with one of the two hard drives failed.
...
the client has 4TB worth of data and its copying/extracting at a snails pace. R-Studio reports it will take 8 days to copy.

Most likely that RAID has a stripe size of one sector. That's the reason of low data extraction speed.

As a solution you can use UFS Explorer and enable caching for source drives before reassembling the RAID 0. After that it will read using "virtual stripe size", which you've set. If reading is linear, you can use a large one – 256-512K.

[sashok07]

"enable caching for source drives before reassembling the RAID 0" can you elaborate on that?

[Dmitri]

"enable caching for source drives before reassembling the RAID 0" can you elaborate on that?

In UFS Explorer right-click on the drives you're extracting the data from and select "Define caching".