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a couple iSCSi questions


talex

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Hi all,

 

I have been running drive pool several years with no issue's on a 2012 Essentials build so to start, thanks for a great product. 

 

I am in the process of upgrading this server to 2012 R2 Standard for several reasons battling with some short comings of essentials v1 unrelated to the file server - I have already gotten the new OS installed as well as drive pool and everything looks good but since I am going through this process I am also in the process of looking into other solutions such as unRaid or freenas or sticking with Windows / drivepool. I plan on running a couple physical VM servers (Dell R710's) and want to use iSCSi for these - freenas has this baked in, unRaid I don't think can do it at all, but Windows Server 2012 R2 can setup iSCSi targets for these VM servers.... sooooooooo....

 

Are there any issue with setting a VHD iSCSi target inside a pool? if there are issue's, what are they?

Would it better to have a drive not in the pool serve this purpose? if so why?

In reverse are there any reasons not to use an iSCSi drive in a pool?

 

freenas is very tempting as it is it's own OS not very vulnerable to attacks but is heavy on the hardware requirements due to having to have the same drives, recommended ECC ram, 1GB per TB etc so I feel like it's more for an enterprise where extreme up time would be the worry but for Home, Small business it almost more of a toy to play with and I cannot see a compelling reason other than Drivepool having to be "hosted" by Windows not to just stick with what I have if iSCSi stuff presents no issue's - thus my questions.

 

I did search iSCSi in the forums and the results did not provide answers so if this has been asked, apologies.

 

1 side note question unrelated to iSCSi this one on the SSD Optimizer plugin - I installed and set up a 240GB SSD as "cache" and the rest of my pool drives are set to archive but when I copy a fairly large file say 5GB and watch performance area in drive pool, it shows drive activity, just not on the SSD - this puzzles me.

 

Thanks ahead of time.

 

Tom

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For the VMs, then I think that should be fine.

 

 

 

from what I have been reading up on freeNas, looking at the performance using basic hardware at least - I see many people getting around 50-85MB's over gig ethernet... with my current setup which is just a gigabyte board using it's built in realtek and standard 7200rpm sata drives - connected through a supermicro SV8 I think it is (4x PCI-e) I regularly get 100-125MBs using Windows server and drive pool so it would seem at least on the face of it that unless you do some serious striping freeNas offers nothing in a performance jump... but is a helluva lot more picky about it hardware... drivepool has worked pretty flawless for me since I bought it right around when released so I am sticking with that - just don't like the idea of having to buy all identical drives and all up front more than anything else, not to mention to many stories about any form of raid where a failure won't rebuild and of course the disks are unreadable as with Drivepool you can mix and match drives and your controller or MB could literally explode and the data is still readable - these are the same reasons I chose Drivepool back when I did, the only real competitor was unraid and it just felt clunky.

 

This may be because of the NICs being used.  A lot of modern network hardware has a number of defaults enabled that cause some pretty poor performance. 

 

Features that include "checksum" and "offload" in the name can do this (they offload the processing to the CPU, via the drivers so... yeah).  Also, improperly configured jumbo frames can cause performance hits. 

 

However, if the poor performance is locally, then that's a different issue. :)

 

As for DrivePool, I'm glad to hear it.  And yeah, it's designed to be simple. And very easily recoverable. ;)

 

 

 

You have a very nice setup - I am heading in the opposite direction - I have my 42U compact rack up on craigslist and have a home built 22U now, also selling my Norco 4220 with the 2 supermicro controllers... moved my AD / DNS server onto a mini ITX Atom based system  - super low power but plenty enough for AD / DNS in a home environment.. and moving my storage server to a 3U case with 10 bays (HDD's are much larger for the buck now then when I last built so I don't need (nor did I ever use) 20 bays... I have around 14TB's of data after deleting many, many, many ancient MSDN and technet ISO files as I don't think I will need 2000 Advanced server or Windows NT or 98 for anything in my lifetime... so that's my setup - 2-Dell R710's Hex Cores with 144GB Ram, the Mini ITX AD.DNS and the 2012R2 Standard w/Drivepool in a generic 3U with 2 5 bay- icy docks... or at least it will be... I just do a synch to external USB's off the server and keep those in a safe in my non-attached garage for "off-site" storage : )

 

 

Thanks.  And I started with a small system. It's grown, and grown. ;) 

 

Though, I can definitely understand the direction.  I have solar, so electricity is "free" and the savings have already paid for the installation costs. 

 

But yeah, it doesn't take a lot to run Active Directory. :) 

 

 

As for using 20 bays .... I'm at 23 bays used right now.   As for deleting ... I joke about "dee leet?" with friends. I like to keep pretty much everything, in case i need it.  It's a trait that I "most likely" picked up from my dad (whom was definitely a hoarder). I only hoard data (and working computers/servers), but still.  Though, it's proven to be very useful in a number of cases. :)

 

But yeah, anything older than Server 2008 is not supported and probably not needed. Besides, Microsoft will still keep them hosted forever, I suspect. 

 

And a very nice setup. Though, if you're keeping the drive stored at home, I'd recommend keeping them in something fire proof/resistant. 

 

Anyways, your saying the cache drive is only good if I have a 2x pool if I have 2x SSD's set to cache? only then will the cache work? I was thinking it worked like the "landing zone" in WHS v1 - where everything copied out landed on that drive and then it was moved... would be good to know as I am in the process of rebuilding the storage server.

 

Yes, I believe so. 

 

If you're using two pools, with no duplication, and you wanted to use SSD Optimizer for both pools, then you need to use two SSDs. Or a SSD partitioned into two volumes. 

 

But if you're using a pool with x2 duplication, then you definitely need two, physical SSDs. 

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I really hate the iSCSI terminology, it's needlessly complicated. 

 

Do you mean storing the VHD's for the iSCSI server?
(absolutely no issue with doing so, but they need to be smaller than the disks in the pool)

Or do you mean adding iSCSI disks to the pool? 
(again, no issues doing so). 

 

I suspect that you do mean the first, due to way that you've worded things.   

And again, no issues with doing so.  However, because StableBit DrivePool stores the actual files on the underlying disks, it means that the files that you're storing need to be smaller than the disks that make up the pool. 

 

Otherwise, you'd need to use a block based solution for the VHD storage (such as Storage Spaces, or a RAID card). 

 

 

 

Freenas is very tempting as it is it's own OS not very vulnerable to attacks 

 

Wrong.  FreeNAS is based on FreeBSD.  Meaning that it uses FreeBSD as the underlying OS, and includes a number of preconfigured applications, services, and modules that make it easier to configure and run for "newer" users.  

 

it as open to attack as any Linux/BSD system.  Which is to say, increasingly so.  Additionally, the more services that are running on it, the more attack vectors exist that can be exploited. 

 

Don't get me wrong, I think it's a very nice package, but "not vulnerable to attacks" is wrong, and a very good way to set yourself up to get screwed. HARD. 

 

As for the hardware, ECC is recommended due to ZFS.  However, ECC is not required, but I would personally recommend it ANY time you're dealing with storage.  RAM is the most likely place that corruption will occur. 

 

As for the 1GB per TB is also wrong, and again related to ZFS.   IIRC, this requirement is if you're using some of the advanced caching options with ZFS.   And you can get away with a lot less, if you're not using these. 

 

Another point, are you familiar with Linux/BSD?  If so, then FreeNAS may be a good option.  But if you're not, you may be setting yourself up for many sleepless nights, ripping your hair out trying to figure out why something isn't working properly. 

 

 

As for home use ... well, you should see my rack. :)  Pictures and specs listed in my signature.  

 

 

1 side note question unrelated to iSCSi this one on the SSD Optimizer plugin - I installed and set up a 240GB SSD as "cache" and the rest of my pool drives are set to archive but when I copy a fairly large file say 5GB and watch performance area in drive pool, it shows drive activity, just not on the SSD - this puzzles me.

 

 

The SSD Optimizer balancer plugin is designed to be a write cache mechanism.  

 

New files are written to the "SSD" drive(s) and then moved off to the archive drives.  Reads and modifies will likely occur from the "archive" drives, depending on when they occur and your balancing settings. 

 

Additionally, if you're using duplication, you need to have a number of SSD drives equal to the highest duplication level in use.

 

Eg, if the pool is x2 duplicated, but you have a large, actively used folder that is x3 duplicated, you'd want to have 3 SSDs in the system. 

 

 

 

This is because "Real Time Duplication" is enabled by default. Meaning that new files and edits are done to all copies of the file, in real time.  So if you don't have enough SSDs, the pool will default to using a slower "archive" drive for new files.  

And this may be what you're seeing. 

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Thanks Chris,

 

WIth the iSCSi - I have a couple of Dell R710's - loaded with ram, each has mirrored SSD's for the OS (one has Hyper-V core, the other vmWare - I want to put the VHD's for the OS's of the VM via iSCSi so I think this will work then and the VHD's will certainly be much smaller than the pool they will reside in, this may or may not work I will have to see as I have all pools 2x duplicated - but who knows, the VM's are mainly SQL instances and I might just decide to slap in some old physical drives for each since I have a few lying around and there are 4 trays in each empty... at a minimum I want them to all use a shared storage target...

 

Not to confuse, I understand that freeNas rides on top of FreeBSD - my point was more that Windows is more vulnerable than Linux is - and my storage box is used just soley for storage, nothing else - I can spin up VM's for other things... and from what I have been reading up on freeNas, looking at the performace using basic hardware at least - I see many people getting around 50-85MB's over gig ethernet... with my current setup which is just a gigabyte board using it's built in realtek and standard 7200rpm sata drives - connected through a supermicro SV8 I think it is (4x PCI-e) I regularly get 100-125MBs using Windows server and drive pool so it would seem at least on the face of it that unless you do some serious striping freeNas offers nothing in a performance jump... but is a helluva lot more picky about it hardware... drivepool has worked pretty flawless for me since I bought it right around when released so I am sticking with that - just don't like the idea of having to buy all identical drives and all up front more than anything else, not to mention to many stories about any form of raid where a failure won't rebuild and of course the disks are unreadable as with Drivepool you can mix and match drives and your controller or MB could literally explode and the data is still readable - these are the same reasons I chose Drivepool back when I did, the only real competitor was unraid and it just felt clunky.

 

You have a very nice setup - I am heading in the opposite direction - I have my 42U compact rack up on craigslist and have a home built 22U now, also selling my Norco 4220 with the 2 supermicro controllers... moved my AD / DNS server onto a mini ITX Atom based system  - super low power but plenty enough for AD / DNS in a home environment.. and moving my storage server to a 3U case with 10 bays (HDD's are much larger for the buck now then when I last built so I don't need (nor did I ever use) 20 bays... I have around 14TB's of data after deleting many, many, many ancient MSDN and technet ISO files as I don't think I will need 2000 Advanced server or Windows NT or 98 for anything in my lifetime... so that's my setup - 2-Dell R710's Hex Cores with 144GB Ram, the Mini ITX AD.DNS and the 2012R2 Standard w/Drivepool in a generic 3U with 2 5 bay- icy docks... or at least it will be... I just do a synch to external USB's off the server and keep those in a safe in my non-attached garage for "off-site" storage : )

 

Anyways, your saying the cache drive is only good if I have a 2x pool if I have 2x SSD's set to cache? only then will the cache work? I was thinking it worked like the "landing zone" in WHS v1 - where everything copied out landed on that drive and then it was moved... would be good to know as I am in the process of rebuilding the storage server.

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Thanks again - yes the one I want to use the SSD's for has 6 discs in a 2x pool - I only added 1 SSD for cache - guess I can remove it and then add it back in when I get another to add, then re-enable the cache plugin.

 

I used to "hoard" but the wife is kind of sick of all the computer stuff lying around - We had 3 gaming teenagers who upgraded alot over the years - the last just finished college and got his own place so I have a ton of hardware I am still sorting through - much of which makes excellent "home server" hardware - probably have about 6 gaming motherboard with as many Phenom Quad Cores lying around and plenty of DDR2 to go with it... and even more gaming video cards - stacks of those.... those not so good for a server though... it's hard to discard that type of stuff so I understand.

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Thanks again - yes the one I want to use the SSD's for has 6 discs in a 2x pool - I only added 1 SSD for cache - guess I can remove it and then add it back in when I get another to add, then re-enable the cache plugin

 

In that pool, yeah, you'd want/need to have 2x SSDs in the pool.   Or disable realtime duplication (which we recommend against doing). 

 

Though, as for SSD prices, they've dropped a LOT. :)

 

 

I used to "hoard" but the wife is kind of sick of all the computer stuff lying around - We had 3 gaming teenagers who upgraded alot over the years - the last just finished college and got his own place so I have a ton of hardware I am still sorting through - much of which makes excellent "home server" hardware - probably have about 6 gaming motherboard with as many Phenom Quad Cores lying around and plenty of DDR2 to go with it... and even more gaming video cards - stacks of those.... those not so good for a server though... it's hard to discard that type of stuff so I understand.

 

Definitely understand this. :)

That and a lot of places don't want you to "just throw away" the hardware, it has to be taken to an electronics recycler... Makes it a pain to dispose of properly. 

 

And the Phenoms could still make good server systems. They're just going to be power hungry. :) 

As for the video cards: Folding@home. Or similar.  I'd say bitcoin mining, but it's a few years too late for that. 

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