Disk initialization = data error (cyclic redundancy check)

[haahof]

I have two different RAID arrays on the StarWind server. I can create targets(virtual disks) and connect to targets on both arrays, but when I go to initialize targets on one of the arrays I consistantly get the following message "Data Error (Cyclic Redundancy Check)"

I should note, that the problematic array is made up of WD drives using the new "Advanced Format" 4K sectors. Is this an issue for Starwind? I am not sure what else the problem could be.

Please tell me there is a solution

-christopher

[haahof]

Since the initial post I have tried connecting from several other machines. I am also throwing the Starport initiator into the mix to see if that has any effect. So far every different attempt yields the same results.

[haahof]

I build a RAID10 and RAID5 with these 4K(Advanced Format) sector drives.

when I set either arrays sector size to 4K( to match the drives) initialization fails in the initiator(both MS and starport)

When I set the arrays sector size to 512b then initialization is happy.

I guess the question is this: What performance penalty, if any, will occur when I force the smaller sector size for the array? Is performance really in the block/stripe sizes?

Any clarification would be helpfull. I am looking to build more of these going forward.

Thanks,

-christopher

[anton (staff)]

Don't use anything except 512 byte sectors with the hard drives. Period. Even assuming post-Windows 2000 NTFS is OK with them.

Key point here is "compatibility" and only then "performance" raises.

Stripe size should match your application. Small stripes are good for databases (except big BLOBs of course) and large ones are better for video capture (non-linear edit & secutiry surveillance for example). Ordinary file server should be somewhere in the middle. So say 16KB-32KB (DB), 64KB-128KB (file server) and 128KB-256KB+ (video).

I build a RAID10 and RAID5 with these 4K(Advanced Format) sector drives.

when I set either arrays sector size to 4K( to match the drives) initialization fails in the initiator(both MS and starport)

When I set the arrays sector size to 512b then initialization is happy.

I guess the question is this: What performance penalty, if any, will occur when I force the smaller sector size for the array? Is performance really in the block/stripe sizes?

Any clarification would be helpfull. I am looking to build more of these going forward.

Thanks,

-christopher

[haahof]

Compatibility is king, and this array was built for backup purposes, so performance is not as big of an issue here. But the next one will have performance in mind.

To clarify what I had asked earlier(and miss typed). I know stripe size has a huge importance on an arrays performance. I know there should be some benefit to the 4k sector sizes as well.
I am concered that overriding the default 4k sectors and emulating 512b sectors on would have a negative impact on performance. From what I have read: http://www.idema.org/_smartsite/externa ... /index.php all new hard drives will have 4k sector sizes. Is forcing the arrays into 512b sectors just not a performance issue? Will StarWind support 4K sectors in future releases? My target and all initiators are win2k8 or win2k8r2 so there is no OS level compatability issues.

Either way, I am up and running now. Thanks for your help.

-christopher

[anton (staff)]

It's not StarWind problem in any case. We lay the image on top of any file system and emulate 512 byte sectors for compatibility reasons.

Compatibility is king, and this array was built for backup purposes, so performance is not as big of an issue here. But the next one will have performance in mind.

To clarify what I had asked earlier(and miss typed). I know stripe size has a huge importance on an arrays performance. I know there should be some benefit to the 4k sector sizes as well.
I am concered that overriding the default 4k sectors and emulating 512b sectors on would have a negative impact on performance. From what I have read: http://www.idema.org/_smartsite/externa ... /index.php all new hard drives will have 4k sector sizes. Is forcing the arrays into 512b sectors just not a performance issue? Will StarWind support 4K sectors in future releases? My target and all initiators are win2k8 or win2k8r2 so there is no OS level compatability issues.

Either way, I am up and running now. Thanks for your help.

-christopher

[haahof]

Thanks for clarifying. One last questions... Does this mean that this mean that Starwind has no plans to support any of the new drives with 4k sectors?

Thanks,

-christopher

[anton (staff)]

StarWind is STORAGE VIRTUALIZATION software. We place container (flat image, CDP engine file set, TP sparse file etc) on the host file system (RAW, NTFS, FAT, EXT 2/3 etc - does not matter, it's up to OS, we rely on the file system driver here) and do EMULATE SCSI-3 compatible hard disk over iSCSI interface. So sector size on the host has NOTHING to do with what we represent to the end user. You may have 32KB sector (actually it's called "ECC block") on DVD+RW random-access formatted media on the host keeping StarWind IMG and say 8KB or 16KB or 512 byte/sector hard disk on the initiator-connected side. We can do 4096 (any size actually...) NOW, we could do it in 2003 as it's just different sector size reported in one SCSI command "read capacity". But! 1) It simply does not have any sense as non-standard sector size does no good to anybody - no performance increase as OS reads and writes with much larger blocks (multiple sectors per single request, 64KB in pre Windows 2003 times and 128KB-256KB in Windows 2008 and Vista storage stacks) 2) It's begging for troubles (exactly what you have). As most of the software was never tested to support anything except 512 byte/sector.

That's why you can use whatever you think is better for you at the target side, place IMG content over NTFS-formatted partition and you'll have perfect, 100% SCSI-3 compatible hard disk at the initiator side. We're taking care of all the performance, emulation, transport etc housekeeping for you.

That's the whole story...

Thanks for clarifying. One last questions... Does this mean that this mean that Starwind has no plans to support any of the new drives with 4k sectors?

Thanks,

-christopher

[haahof]

That was my understanding, which brings be full circle to my original problem. When the array that holds my ISCSI images is left with its native 4k sector size, none of my initiators can initialize the disk.

The disk and volume on the server where the images reside that seems to be causing the problem. You say its up to the OS to to manage the underlying environgment in which the ISCSI images are stored. Thats sounds good, but that is also where I am running into problems. The OS(server 2008) has no problem reading/writting, serving apps etc.... but ISCSI images served from the 4k sector disk wont fly. If I delete and recreate the the array and set the sector size to 512b, reattach the images to the StarWind server, then the initiators can initialize the disk. This isn't about initator side volume formatting, I am not even getting that far.

For what its worth, here is more detail on the environment that I am using to create, recreate the issue:

Win2k8
Rocket RAID 622
5x WD15EARS (tried RAID5, and RAID1+0)

Again, thanks for working with me on this. If we are talking past each other or frustration is setting in on your end, I can get in touch with support on Monday. I may be having trouble explianing this issue to you correctly.

-christopher

[anton (staff)]

If you create an image with file system cache setting set to OFF writes have to be logical block aligned and that's could be a problem. Please have StarWind logs under hands on Monday (you can even start yourself sending them zipped to support@starwindsoftware.com) and we'll check what could be done here at either (initiator or target) side. Thanks!

That was my understanding, which brings be full circle to my original problem. When the array that holds my ISCSI images is left with its native 4k sector size, none of my initiators can initialize the disk.

The disk and volume on the server where the images reside that seems to be causing the problem. You say its up to the OS to to manage the underlying environgment in which the ISCSI images are stored. Thats sounds good, but that is also where I am running into problems. The OS(server 2008) has no problem reading/writting, serving apps etc.... but ISCSI images served from the 4k sector disk wont fly. If I delete and recreate the the array and set the sector size to 512b, reattach the images to the StarWind server, then the initiators can initialize the disk. This isn't about initator side volume formatting, I am not even getting that far.

For what its worth, here is more detail on the environment that I am using to create, recreate the issue:

Win2k8
Rocket RAID 622
5x WD15EARS (tried RAID5, and RAID1+0)

Again, thanks for working with me on this. If we are talking past each other or frustration is setting in on your end, I can get in touch with support on Monday. I may be having trouble explianing this issue to you correctly.

-christopher

[haahof]

Success!

I didn't want to tweak anything until I had everything up and running so I left everything defaulted including the cache set to off.

Turning on caching fixed the problem.

Thanks for the help.

-christopher

[anton (staff)]

Unfortunately this is WORKAROUND and not a solution... Everything should work AS IS (unbuffered).

Success!

I didn't want to tweak anything until I had everything up and running so I left everything defaulted including the cache set to off.

Turning on caching fixed the problem.

Thanks for the help.

-christopher

[haahof]

The success was short lived... Not sure how it worked.

I ended up blowing away the array and rebuilding it using 512 byte blocks... I just need it working for now.

-christopher

[anton (staff)]

Thank you for this update. We're checking what could be done here.

The success was short lived... Not sure how it worked.

I ended up blowing away the array and rebuilding it using 512 byte blocks... I just need it working for now.

-christopher

[claymen]

I have the same issue here. 4k sector HDD fails.

And it's not just with StarWind even Microsofts VHD's fail to work on a 4k disk. Which is amusing that it breaks windows backup entirely as it relies on this.