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nested raid 10/50/60

Software RAID information and help
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encgeek
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nested raid 10/50/60

#1

Post by encgeek »

Hello,

I'm new to nas4free. Right now i'm experimenting and learning it under an esxi 5.1 VM so that i can get used to how things are setup and configured...

Creating a raidz2 seems to be pretty straight forward...

I have three requirements that i'll be using nas4free for (Please note this is all home built / whitebox type hardware for my home lab and some production vm's, there is no server grade hardware involved and for this task there won't be)

1. ISCSI target - 8 x 1TB 7200 RPM Sata drives, 8 Gigs RAM. May also be used for lite file server storage (cifs/samba). The existing iscsi target has 8x 1TB drives in raid 10. 8 GB DDR2 800, amd quad core at 2.5 Ghz. I could use that same software raid 10 configuration in the nas4free box however I'd like to test and see how a nested RAID 50 / RAID 60 setup would perform. Currently I am using Ubuntu 12.04 LTS with open-iscsi for this purpose however i want to migrate to nas4free because of the advantages that it may provide.

2. CIFS/Samba File Server 1 on esxi 5.1 . VM will have 2-4G allocated with 8 x 2TB 7200 RPM Sata2 drives. I am assuming raidz2 for this (Current setup is ubuntu 12.04 with raid 6) Data Integrity most important over performance. note: Sata drives are raw device mapped in esxi for performance and used directly by the VM.

3. CIFS/ Samba File server 2/ backup storage on esxi 5.1 2G allocated with 5 x 1 TB 7200 RPM Sata2 drives and 3x 1.5 TB 7200 Sata2 drives for backup storage (Currently these are both in software RAID5). note: Sata drives are raw device mapped in esxi for performance and used directly by the VM.


Question 1: I haven't found any documentation on how to configure the nested software raid levels. Could someone help? (Raid 10/50/60)

Question 2: Is there a way to convert linux logical volumes for use on nas4free as a volume? Note that i am not familiar with ZFS at all and i'm just now learning it's structure (Vdev's, pools, etc) . I've searched the forums and so far haven't found anything. My existing iscsi-target consists of multiple linux lvm's presented to the esxi boxes as separate LUN's for each VM. For example is there a way to ssh / dd from the existing iscsi target box to the volume on the nas4free box?

Question 3: Also does anyone know how raidz / raidz2 would perform for iscsi targets? I have always used raid 10 under linux because the slower write performance with software raid 5 / 6 was fairly apparent.

Thanks much!!

-Scott

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Re: nested raid 10/50/60

#2

Post by al562 »

Hi Scott,

Welcome to the NAS4Free forum. Below is information you may find helpful.

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Please make note of rule #11, I will make 1 exception in your case ;) .
encgeek wrote:Question 1: I haven't found any documentation on how to configure the nested software raid levels. Could someone help? (Raid 10/50/60)
Sure, SoftRAID 10 is simple, create 2 SoftRAID1 arrays, then create a SoftRAID0 on top of them, format it and start using it. 50 is done pretty much the same way. 60 is problematic because it depends on your definition of what RAID6 is. We can build arrays with 5 discs, but I have never done it so am not sure how you specify the 2nd parity block, but it might be in there somewhere, we'd have to look and see. I can't really see why you'd want to build a server as you describe using anything more than SoftRAID1 or RAIDz, but I'll help if I can.
encgeek wrote:Question 2: Is there a way to convert linux logical volumes for use on nas4free as a volume?
None that I'm aware of.
encgeek wrote:For example is there a way to ssh / dd from the existing iscsi target box to the volume on the nas4free box?
This sounds possible, but I have not tried it and am not aware of anyone who claims to have. The safest way and I laugh when I say safest, is to use ZFS and make sure software versions are identical from Linux to FreeBSD. If ZFS versions are identical, the arrays should migrate over, but I've never tried it and only heard it done once from Solaris, about 3 years ago. There are lots of safer ways to transfer your data though.
encgeek wrote:Question 3: Also does anyone know how raidz / raidz2 would perform for iscsi targets? I have always used raid 10 under linux because the slower write performance with software raid 5 / 6 was fairly apparent.
Generally from what I've seen, RAIDz and RAIDZ2 performance is similar to the equivalent SoftRAID level except that writes will be a little slower due to the extra error checking. There are many topics in the forums regarding ZFS performance/tuning, you may find more specific answers by reading some of them.

Hope some of that helped.

Regards,
Al

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shakky4711
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Re: nested raid 10/50/60

#3

Post by shakky4711 »

Hi,

I am not able to give any feedback about the esxi issue, all my systems run on native hardware.
When speed in important read this about mirrors: http://constantin.glez.de/blog/2010/01/ ... still-best

And this about ZFS setup recommendations: https://sites.google.com/site/eonstorage/zpool_notes

Shakky

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Re: nested raid 10/50/60

#4

Post by alexplatform »

2. CIFS/Samba File Server 1 on esxi 5.1 . VM will have 2-4G allocated with 8 x 2TB 7200 RPM Sata2 drives. I am assuming raidz2 for this (Current setup is ubuntu 12.04 with raid 6) Data Integrity most important over performance. note: Sata drives are raw device mapped in esxi for performance and used directly by the VM.
Are you planning to have your hypervisor and mass storage on the same physical server? This is a bad idea on many levels, and is not in anyone's best practices, if for no other reason that your hypervisor must boot, mount storage for the NAS guest, boot the NAS, and only then have access to the mass storage it provides. Consequently, expect virtually no support or consistent performance. Lastly, RDM behavior under esxi is poor and works only on specific hardware.
3. CIFS/ Samba File server 2/ backup storage on esxi 5.1 2G allocated with 5 x 1 TB 7200 RPM Sata2 drives and 3x 1.5 TB 7200 Sata2 drives for backup storage (Currently these are both in software RAID5). note: Sata drives are raw device mapped in esxi for performance and used directly by the VM.
Would it not make more sense to have all that storage on your NAS target, serving the respective clients (vmware, windows workstations) directly? As for backup, for it to be of actual use you probably want it on a seperate machine anyway. to have your cake and eat it to, you may want to consider HAST.

Now, as to your questions:
Question 1: I haven't found any documentation on how to configure the nested software raid levels. Could someone help? (Raid 10/50/60)
http://www.zfsbuild.com/2010/06/03/howt ... ted-zpool/
Question 2: Is there a way to convert linux logical volumes for use on nas4free as a volume?
No. ZFS is an integrated LVM/File system. Linux RAID LVM is not related to the file system at all.
My existing iscsi-target consists of multiple linux lvm's presented to the esxi boxes as separate LUN's for each VM. For example is there a way to ssh / dd from the existing iscsi target box to the volume on the nas4free box?
Since iSCSI is block storage, this is possible (create the new target, map the old one, dd old to new.) Depending on the data stored on the target, it may be better to simply rsync the payload to its new home.
Question 3: Also does anyone know how raidz / raidz2 would perform for iscsi targets?
Based on your questions I expect you already know how unanswerable that is. It performs very well. or very poorly. or both. With as many variables involved with your observed performance, all of the above.

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Re: nested raid 10/50/60

#5

Post by encgeek »

I thank everyone for their inputs . I have decided to setup the iscsi target server with 8 x 1 TB drives... This will run on real hardware (not vm'ed) with 8GB DDR2, amd quad core x4 9850, etc.

I need help in deciding how best to setup the actual storage on the drives. I thought about nested software raid 10... BUT... does zfs have a similar setup? Should i nest 4 raid 1 mirrors with raid zero on top to get the raid 10 effect? Should I use zfs volumes to service individual lun's or one volume to serve as a datastore for the esxi boxes?

I would rather not use software raid 5 or raidz1 for obvious reasons... Raidz2 is a possibility but i'm concerned about performance... even though this box will be used for my home lab office to serve iscsi targets to my windows 7 box, and two esxi 5.1 hypervisors. I currently enjoy read and write speeds of 80-100 MB's per second in the current configuration (Ubuntu 12.04 open-iscsi with the same drives in linux software raid 10).

Thanks for anyone who has any advice.

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Re: nested raid 10/50/60

#6

Post by shakky4711 »

Hello,

Read this
https://sites.google.com/site/eonstorage/zpool_notes and this
http://constantin.glez.de/blog/2010/01/ ... still-best

When speed is your main target you learn that the best choice is to create vdev-mirrors and put them into one pool. The system stripes data automatically over these mirrors.
Next tuning tasks could be to add two SSD as ZIL device and add a separate cache drive.

When money is not a problem create tripple mirros
As an extra bonus, a 3-way mirror gives you 3x read performance. Cool!
Such a setup should make every speed-junky happy...

Next tip, increase RAM from 8GB to 16GB and use Intel Pro1000 only, hope the rest from your network and clients is capable to cooperate with such a stron storage machine :lol:

Shakky

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