Alternative way of doing parity?

[flixxx]

Hello,

 

i'd like to know if there is a better way to run a parity check on unraid 4.7?

 

Currently it takes me approximately 2 days to do a full parity check and during that time my HD movies run choppy on my media center so I have to refrain from watching any HD content. Is there an alternative way of doing a parity check in phases or some alternative where I can schedule it to do one for 3 hours a night?

 

My theory is a no because you may write new content to the parity but maybe something is available out there that I don't know about.

 

Regards,

 

Flixxx

[prostuff1]

Hello,

 

i'd like to know if there is a better way to run a parity check on unraid 4.7?

 

Currently it takes me approximately 2 days to do a full parity check and during that time my HD movies run choppy on my media center so I have to refrain from watching any HD content. Is there an alternative way of doing a parity check in phases or some alternative where I can schedule it to do one for 3 hours a night?

 

My theory is a no because you may write new content to the parity but maybe something is available out there that I don't know about.

 

Regards,

 

Flixxx

um... a parity check should not take that long, unless you are perhaps running everything from a PCI bus based system with huge drives.

 

Post your system specs and a syslog

[flixxx]

Hello,

 

i'd like to know if there is a better way to run a parity check on unraid 4.7?

 

Currently it takes me approximately 2 days to do a full parity check and during that time my HD movies run choppy on my media center so I have to refrain from watching any HD content. Is there an alternative way of doing a parity check in phases or some alternative where I can schedule it to do one for 3 hours a night?

 

My theory is a no because you may write new content to the parity but maybe something is available out there that I don't know about.

 

Regards,

 

Flixxx

um... a parity check should not take that long, unless you are perhaps running everything from a PCI bus based system with huge drives.

 

Post your system specs and a syslog

 

Sure here are the system specs;

 

 

parity WDC_WD2002FAEX-0_WD-WMAY01642482 1,953,514,552

disk1 Maxtor_6H500R0_H80J9HGH                                 488,386,552      

disk2 WDC_WD5000AAKS-7_WD-WMASY4103612         488,386,552

disk3 WDC_WD1001FALS-0_WD-WMATV5570723 976,762,552

disk4 WDC_WD15EARS-00S_WD-WCAVY1930651 1,465,138,552

disk5 WDC_WD6400AAKS-0_WD-WCASY0373935 625,131,832

disk6 Hitachi_HTS54505_100410PBN40017CZKJXE 488,386,552

disk7 WDC_WD20EARS-00M_WD-WCAZA8997232 1,953,514,552

disk8 WDC_WD20EARS-00M_WD-WMAZ20043234 1,953,514,552

cache WDC_WD2000JB-00GVA0_WD-WMAL81014852 195,360,952

 

Motherboard: Intel BOXD945GCLF2 MINI-ITX DDR2 945GC Dual Core Atom 1PCI Motherboard

SATA Card: Supermicro AOC-SAT2-MV8 8 Port SATA Card Pcix 64BIT 133MHZ RAID

 

Parity and Cache are plugged straight to the motherboard.

2 IDE drives

All other drives are plugged in to a PCI Sata card; Supermicro AOC-SAT2-MV8 8 Port SATA Card Pcix 64BIT 133MHZ RAID

 

 

 

Parity runs at about 2.5 MB a sec.

Parity drive is the fastest one = Black

8.6TB of storage.

 

[prostuff1]

No wonder that is so slow.  You are running a lot of drives off the PCI bus.  You are pretty much SOL for speeding this thing up, except for buying some new parts.

[Johnm]

You are completely at the mercy of your hardware. While the Atom is fast enough, the PCI slot is a huge bottleneck.

 

the only other option i can think of short of a server rebuild, possibly adding a USB S.N.A.P. drive to the system and putting a copy of some of your media on that to watch during parity checks..

 

sorry...

[dgaschk]

All of the PCI slots can only support a single drive with no performance degredation.

[Johnm]

All of the PCI slots can only support a single drive with no performance degredation.

 

That is the problem.

his board only has one PCI slot and nothing else. it an ITX board.

For any real performance boost (assuming he wanted to stay mITX) is to scrap the mobo and PCIx card and go with a PCIe combo.

 

[joe90]

the only alternative to get your box to be faster is to move most of the stuff  to your bigger drives

 

so:

 

parity  WD2002FAEX1,953,514,552 

disk1  WD15EARS  1,465,138,552 

disk2  WD20EARS  1,953,514,552 

disk3  WD20EARS  1,953,514,552

disk4  WD20EARS  1,953,514,552 

cache  WD2000JB  195,360,952 

 

and buy another 2TB drive (disk4)

 

so you'd be at around 7.5TB with a cache drive that is not used while doing parity and bring your speed around 35-40Mb/s

 

or remove the cache drive to get 9.5TB and lower it some more to 28/33 MB/s parity check speed

 

 

 

 

[MrD1234]

That 133 Mhz 64bit card is only running at 33Mhz 32 bit (i.e. an eight of its rated performance)

[SSD]

You are completely at the mercy of your hardware. While the Atom is fast enough, the PCI slot is a huge bottleneck.

 

the only other option i can think of short of a server rebuild, possibly adding a USB S.N.A.P. drive to the system and putting a copy of some of your media on that to watch during parity checks..

 

sorry...

 

Or you could just copy some media files to a workstation instead of adding yet another drive to the unRAID box.

 

In your situation, the only way to speed up parity checks is to drop the drive count.  You've got 3 500G drives and 1 640G drive that could almost be replaced with one 2T drive.  Not sure if you are close to the edge with free space, but dropping 3 drives from the configuration would definitely help.  And replacing four older drives, 2 of them IDE, with one new one is a good step in reliability.

 

From a long term perspective, through, parity checks will only get more painful with 3T and larger drives.  I'd definitely start researching ITX boards with a PCIe slot (4x minimum or 8x preferred).  No huge rush, but find the ones that would work and start monitoring them looking for a good deal.

 

For new users reading, although a PCI laden system such as this one IS slow for parity builds and checks, it is not slow for more typical users like reading and writing.  If you are buying a new MB, I definitely recommend one with PCIe slots, but if you are looking to use an aging motherboard in your parts bin for an initial build, I would have no problem with a 3 drive build on the PCI bus to get your feet wet.

[flixxx]

Thanks for all the replies!

 

I have a Asus p5wd2 lying around that I might just switch it with. I'll just need a PCIe SATA card (Probably the Supermicro AOC-SASLP-MV8 recommended from this http://lime-technology.com/forum/index.php?topic=12404.0)

 

It's a shame though, it's not that long ago that I bought that PCI sata card hoping that it would do the trick.

[prostuff1]

Thanks for all the replies!

 

I have a Asus p5wd2 lying around that I might just switch it with. I'll just need a PCIe SATA card (Probably the Supermicro AOC-SASLP-MV8 recommended from this http://lime-technology.com/forum/index.php?topic=12404.0)

 

It's a shame though, it's not that long ago that I bought that PCI sata card hoping that it would do the trick.

The problem is it is not really a PCI card it is a PCI-X card meant to run in a PCI-X slot which has CONSIDERABLY more bandwidth than a normal PCI card.  Those cards are generally used in server boards that have PCI-X slots.

[dgaschk]

Thanks for all the replies!

 

I have a Asus p5wd2 lying around that I might just switch it with. I'll just need a PCIe SATA card (Probably the Supermicro AOC-SASLP-MV8 recommended from this http://lime-technology.com/forum/index.php?topic=12404.0)

 

It's a shame though, it's not that long ago that I bought that PCI sata card hoping that it would do the trick.

The problem is it is not really a PCI card it is a PCI-X card meant to run in a PCI-X slot which has CONSIDERABLY more bandwidth than a normal PCI card.  Those cards are generally used in server boards that have PCI-X slots.

 

This board will support a single drive in a PCI slot or 7-8 in a PCI-X slot.

[BobPhoenix]

Thanks for all the replies!

 

I have a Asus p5wd2 lying around that I might just switch it with. I'll just need a PCIe SATA card (Probably the Supermicro AOC-SASLP-MV8 recommended from this http://lime-technology.com/forum/index.php?topic=12404.0)

 

It's a shame though, it's not that long ago that I bought that PCI sata card hoping that it would do the trick.

The problem is it is not really a PCI card it is a PCI-X card meant to run in a PCI-X slot which has CONSIDERABLY more bandwidth than a normal PCI card.  Those cards are generally used in server boards that have PCI-X slots.

 

This board will support a single drive in a PCI slot or 7-8 in a PCI-X slot.

At full speed yes.  I would say this would work fine in a JBOD system like my SageTV server with individual drives.  I have it setup that way now and it works great.  Yes when accessing multiple drives at once like a parity check in unRAID will slow it down but it does work fine for me.  I just wouldn't use it in a PCI slot with unRAID.