billthornton

Long Format/resync time for win2003 raid 5 ?

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I have set up 6x500gb sata 150 disks on windows 2003 server, using only software raid 5. The pc is an old athlon xp 1.1ghz with 1gb ram.

First i tried it took about 2 hours to 'resynchronize' about 2% after a quick format.

So i thought maybe there was a problem with the disks, so i tried again with a full format. The format has now been running about 28hrs and its at 26%!

Does this seem right??

Has anyone done this before ? and if so how long did it take for you?

Thanks for any help.

Bill

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No, can't honestly say it did take that long for me.

Took me about 3 hours to fully sync a 4x160GB RAID array though "back when" I had a bunch of ol' IDE disks on a crappy PCI controller.

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That's pretty much par for the course with software raid5.

I just transferred an older raid5 array from a dual p2-400 rig to my new Core2 E6400 running WinXP Pro 64-bit.

I'm currently resynching a raid5 array with 5 250GB IDE drives on two Promise Ultra133 TX2's, it's at 36% after running for 2 hours. So probably 5.5hours on my shiny new 2.13Ghz Core2.

I remember originally formatting the array on my old dual P2-400 rig and it took a good 18-20 hours.

BTW, you can't normally run raid5 on WinXP Pro, but I used the "Tom's Hardware" hack to enable it on both systems.

HTH,

Ben

Edited by ButtonPuncher

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Thanks for the replies.

For information it has now finished, it took about 36hrs total, to format and resynch. So it must have gone fast on the last bit.

One drive had errors so i am now running a full scan (2 hours into it now).

Bill.

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It takes a long time, but 36 hours is too long I suspect. It took nowhere near that long for me to deal with 5x120gb once. If you think one of the drives is broken it probably is!!!

Edited by Loomy

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Such is life with larger drives of today... RAID 5 rebuilds are a pain.. Some hardware based RAID cards can lessen these times based on their own technology, but it can get pricey.

Just think, it'll only get worse as drives get even larger.

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That's pretty much par for the course with software raid5.

Nah, it's a problem specifically with Windows 2003 and earlier's RAID5 implementation, which appears to be either artificially speed limited or crippled by a very poor implementation.

Linux, Solaris, etc have no trouble using up all the bandwidth they can get. My RAID5 arrays achieve 120mbytes/sec of throughput, and they achieve no more than 120mbytes/sec only because of a controller limitation in the Sil3132 PCI Express SATA controller. If each drive were connected to the controller by itself (instead of the port multiplier), performance would be much higher.

Such is life with larger drives of today... RAID 5 rebuilds are a pain.. Some hardware based RAID cards can lessen these times based on their own technology, but it can get pricey.

No, hardware RAID cards have no special technology making them faster. The nicer cards do have a fast CPU connected to the drives via a fast bus, so they can rebuild (and do any operation) fast. Given enough bus bandwidth and an uncrippled HBA, a software RAID implementation can do the same thing.

Edited by dfv

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My Windows XP and Windows 2003 Software RAID had no problem using up all the bandwidth it could get, with a 1.1Ghz Athlon Thunderbird it easily maxed out my PCI bus.

Best case scenario on ButtonPuncher's rig I'd estimate to be around 3.5-4 hours, so 5.5 isn't far off.

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Such is life with larger drives of today... RAID 5 rebuilds are a pain.. Some hardware based RAID cards can lessen these times based on their own technology, but it can get pricey.

No, hardware RAID cards have no special technology making them faster. The nicer cards do have a fast CPU connected to the drives via a fast bus, so they can rebuild (and do any operation) fast. Given enough bus bandwidth and an uncrippled HBA, a software RAID implementation can do the same thing.

I beg to differ based on postings from various manufacturers, and seminars with W. Curtis Preston who is one of the industries most knowledgable people when it comes to storage technology.

HP claims faster calculations during the rebuild with their technology. Yet, I can find no proof of their technology. However, their smart array controllers have been around a very long time, over a decade! They are not in the same class of RAID cards that many people here talk about for their home systems. So it's quite possible that their claims are not just marketing fluff.

NetApp and HP both have their rapid rebuild technology allowing you to work while an array is still rebuilding with minimal impact to end users. You just can't do many of the advanced features within the RAID card while it's tasked with the rebuild. Not quite a acceleration technology, but a good thing to have in general.

I even recall one of my EMC SAN's claiming something similar to HP and their accelerated rebuild technology. Typically when talking about EMC, Hitachi, or <insert large SAN manufacturer> all of their technology is built into their controller cards, I mean their entire technology is based on that, as well as all sales are based on focusing how their controllers are faster/better/more scalable over anyone elses..

So with that said, typically rebuild times are based on drive speeds, capacities, cluster sizes, etc... It's not unfathomable that some geeky PhD created some algorithm for pre-calculating parity information, and possibly allowing for faster rebuild times based on said algorithm...

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