XenServer 7: best practice: noob question
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@FATeknollogee said in XenServer 7: best practice: noob question:
- Installing XS: I'd like to use 2x 80GB SSD mirrored (aka RAID1). **Do not want to use USB flash drive
- Is it ok to use "fake RAID" on the motherboard (Intel or LSI)?
- What is the best practice?
FakeRAID is never recommended for anything in production, ever. It's conceptually a bad idea.
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@FATeknollogee said in XenServer 7: best practice: noob question:
- For Virtual Machine storage:
- Should the drives (assume multiple) be attached to a controller via RAID controller or HBA?
- What is best practice?
HBA is for external drives. XenServer only officially supports hardware RAID controllers but includes enterprise software RAID. Either are fine. But generally you want hardware RAID in the SMB space.
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@FATeknollogee said in XenServer 7: best practice: noob question:
@DustinB3403 said in XenServer 7: best practice: noob question:
Use a USB flash drive, it's super simple to clone for backup purposes and easily replaced. Using fake RAID is completely worthless.
With XenServer you could do RAID1 SSD, and then RAID10 (winchester) drives using MDADM. Hardware raid is recommended though.
Why waste the money for SSDs for the boot device? USB is so CHEAP, and so simple to backup and clone.
I hear you on the fake RAID.
The RAID 1 or 10 you mentioned, it that for use as boot drive & VM storage?
I know USB is cheap, but I have a few small SSDs laying around.
IF you go with booting XenServer off of the disks, then it should always be thrown onto the same array as the VM storage. Anything else is just throwing away speed and capacity from your VMs for no reason.
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Booting from USB is good. Booting from the same large array as the VMs is good. The only scenario that really isn't okay is having a RAID set just for booting XenServer. And if you DO do that, the worst option is to use SSD. You would always use the slowest, cheapest disks that you could find, SSD would be the opposite. But you would never do that either way.
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@DustinB3403 said in XenServer 7: best practice: noob question:
RAID1 if you were going to do a RAID'd boot partition. (huge waste of resources though) and RAID10 for the VM storage if your drives are "classic Winchester drives. Otherwise if you're using SSD for the VM storage RAID 5.
I thought RAID5 was a no-no. I'm pretty sure I've read that somewhere on these forums.
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@FATeknollogee said in XenServer 7: best practice: noob question:
@DustinB3403 said in XenServer 7: best practice: noob question:
RAID1 if you were going to do a RAID'd boot partition. (huge waste of resources though) and RAID10 for the VM storage if your drives are "classic Winchester drives. Otherwise if you're using SSD for the VM storage RAID 5.
I thought RAID5 was a no-no. I'm pretty sure I've read that somewhere on these forums.
RAID5 Winchester is a No-no because spinning drives (classic SATA) have all kinds of issues with RAID5 like URE issues.
RAID5 with SSDs are perfectly safe.
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@FATeknollogee said in XenServer 7: best practice: noob question:
@DustinB3403 said in XenServer 7: best practice: noob question:
RAID1 if you were going to do a RAID'd boot partition. (huge waste of resources though) and RAID10 for the VM storage if your drives are "classic Winchester drives. Otherwise if you're using SSD for the VM storage RAID 5.
I thought RAID5 was a no-no. I'm pretty sure I've read that somewhere on these forums.
RAID 5 is a no no on spinning rust. The things that rule it out for traditional Winchester drives do not impact it for SSDs. So it is the primary RAID option for SSD arrays.
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@scottalanmiller said in XenServer 7: best practice: noob question:
HBA is for external drives. XenServer only officially supports hardware RAID controllers but includes enterprise software RAID. Either are fine. But generally you want hardware RAID in the SMB space.
I asked about HBAs because in the MSFT world with Storage Spaces HBAs can be used for internal drives.
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@FATeknollogee said in XenServer 7: best practice: noob question:
I asked about HBAs because in the MSFT world with Storage Spaces HBAs can be used for internal drives.
HBAs are hardware so there isn't an Windows world or anything. Are they just calling SAS adapters HBAs?
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They are not technically incorrect, you CAN call those things HBAs. But no one does. We normally use the term HBA to denote external connections only. Otherwise we'd always call them SAS adapters to avoid confusion. I think HBA only works as a term when it's for external connections.
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HBAs: The LSI 9205-8i/9207-8i/93xx family of cards or flashing the LSI "IR" cards to "IT" mode.
http://www.avagotech.com/products/server-storage/host-bus-adapters/#tab-overview -
@FATeknollogee said in XenServer 7: best practice: noob question:
HBAs: The LSI 9205-8i/9207-8i/93xx family of cards or flashing the LSI "IR" cards to "IT" mode.
http://www.avagotech.com/products/server-storage/host-bus-adapters/#tab-overviewYeah, they are trying to sound cooler than just saying "SAS Adapter." Just SAS Adapters.
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@FATeknollogee said in XenServer 7: best practice: noob question:
@scottalanmiller said in XenServer 7: best practice: noob question:
HBA is for external drives. XenServer only officially supports hardware RAID controllers but includes enterprise software RAID. Either are fine. But generally you want hardware RAID in the SMB space.
I asked about HBAs because in the MSFT world with Storage Spaces HBAs can be used for internal drives.
They CAN be, but it is FAR less recommended there. Using Storage Spaces is just a fancy MS world marketing term for software RAID. And MS Software RAID is not considered to be enterprise ready. Linux Software RAID is and has been for decades.
So if on XenServer you hear hardware RAID recommended over software RAID, that's a minor recommendation. In the Windows world, hardware RAID is the only viable consideration. Using Storage Spaces today is... reckless. It's not just not a proven technology, it's a known bad technology with 20+ years of problems. The entire hardware RAID industry exists specifically because Windows Software RAID (now called Storage Spaces) isn't ready for prime time and should be avoided. If it wasn't for Windows and Novell Netware needing hardware RAID to compete, no one would bother making it.
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@FATeknollogee said in XenServer 7: best practice: noob question:
@DustinB3403 said in XenServer 7: best practice: noob question:
- Best practices dictates that you install to USB, and clone USB to "backup USB"
- No never use fake raid
Using this method? http://mangolassi.it/topic/8537/how-to-clone-a-xen-usb-on-windows
I assume there is no way to make the clone without removing the USB stick from the XS box?
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@scottalanmiller said in XenServer 7: best practice: noob question:
They CAN be, but it is FAR less recommended there. Using Storage Spaces is just a fancy MS world marketing term for software RAID. And MS Software RAID is not considered to be enterprise ready. Linux Software RAID is and has been for decades.
So if on XenServer you hear hardware RAID recommended over software RAID, that's a minor recommendation.
For XS, if the Linux software RAID is better, why not just always recommend that option & why is this not a supported option?
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@FATeknollogee said in XenServer 7: best practice: noob question:
@FATeknollogee said in XenServer 7: best practice: noob question:
@DustinB3403 said in XenServer 7: best practice: noob question:
- Best practices dictates that you install to USB, and clone USB to "backup USB"
- No never use fake raid
Using this method? http://mangolassi.it/topic/8537/how-to-clone-a-xen-usb-on-windows
I assume there is no way to make the clone without removing the USB stick from the XS box?
Of course you'd have to remove it from the box. At least using that method.
You might be able to do it with DD, but you wouldn't want to do it while the system was running.
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@FATeknollogee said in XenServer 7: best practice: noob question:
@scottalanmiller said in XenServer 7: best practice: noob question:
They CAN be, but it is FAR less recommended there. Using Storage Spaces is just a fancy MS world marketing term for software RAID. And MS Software RAID is not considered to be enterprise ready. Linux Software RAID is and has been for decades.
So if on XenServer you hear hardware RAID recommended over software RAID, that's a minor recommendation.
For XS, if the Linux software RAID is better, why not just always recommend that option & why is this not a supported option?
Because Hardware RAID is more easily protected, with built in batteries.
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@DustinB3403 said in XenServer 7: best practice: noob question:
For XS, if the Linux software RAID is better, why not just always recommend that option & why is this not a supported option?
Because Hardware RAID is more easily protected, with built in batteries.
What makes the Linux software RAID better?
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@FATeknollogee said in XenServer 7: best practice: noob question:
@DustinB3403 said in XenServer 7: best practice: noob question:
For XS, if the Linux software RAID is better, why not just always recommend that option & why is this not a supported option?
Because Hardware RAID is more easily protected, with built in batteries.
What makes the Linux software RAID better?
Well it's free, so cost is one way to call it better. It's been around forever and is incredibly stable and well documented.
Ways it's worse is that if the system loses power, so do the array instantly. So you risk database corruption etc.
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Does it have better performance & is it easier to setup?
