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pidyna.v
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Which RAID level for virtual machines in EqualLogic 5000e

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I have `Dell EqualLogic PS5000E iSCSI Array`. I have connected this `SAN` to servers directly. I used `Jumbo Frames`. In this case, everything is ok. My storage is `~25TB`. Now, i need to choose, which RAID level i have to use. SAN proposes only 3 levels: `6`, `50`, `10`. I have 16 hdd-s with `~1.8TB` per each disk.
Which `RAID` level can you advice for virtualization and for work with databases ?
Also, better to configure two raid levels. But `SAN` creates only one default storage pool with all our disks.
If you know other way to confgigure two arrays, it will very nice

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dwilliam62
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Re: Which RAID level for virtual machines in EqualLogic 5000

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Hello, 

 There is no way to create different RAID levels on one physical array.  The entire array will be one RAID level. 

 Re: Directly Attached.  l hope you are using a switch in between the servers and servers?  Directly attaching a server to the array isn't supportable.  You need the switch for proper buffering, flowcontrol and so that both controllers can be wired into the switch in case of failover.  Ideally there would be two swtiches for better redundancy, If you are using a switch what MFR/Model switch are you using? 

re: RAID level.  The only one you should consider is RAID6.  With an old array, and greater than 1TB drives, only RAID10 and RAID6 should ever be considered.  The risk of double faulting the drive is too great.  Unless you do not care about the data at all, if there is no production data on it and you can rebuild in the event of faulted beyond recovery failure of two drives. 

 FYI: 25TB is raw, after the overhead, the configuration and diag area and 2x drives for RAID6 parity and 1 spare you'll be down around 20TB usable at RAID6.  RAID50 will be less, since there are two spares in RAID50. 

 What Virtualization platform are you planning on using? 

  Regards, 

Don 

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pidyna.v
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Re: Which RAID level for virtual machines in EqualLogic 5000

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Hello, thanks for your answer. No, i have two servers `dell r620`.
First port of `dell r620` i have connected to my local network, second port of `dell r620` i connected to first module of san, third port of `dell r620` i connected to second module of san. I made "Jumbo Frame" on second and third port of `dell r620`, i made isolate network on these ports and it really works. I have connected to SAN, i have configured storage, and i tried to physically disconnect link from first module of SAN, and the second module of SAN was received role of first module with minimal ping. And it works without switch. Why i can't use this SAN directly ?
According to virtualization, i am using Hyper-V role of Windows Server.
Also, i tried to make volume and to connect from Windows server and it works! Because i don't have free 1G-10G switch for this role.

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dwilliam62
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Re: Which RAID level for virtual machines in EqualLogic 5000

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Hello,

 You are very welcome.  

re: Switch. Connecting a volume and formatting it involves very little data.  When you start to use is when problems will start.  Also the servers should each have two connections to the SANs for MPIO.  In case of cable or NIC failure. 

 I have been with Dell EQL  for over 15 years.  No one attempting to do what you are has been successful in production.  Used GbE switches that will do the job well, are around $100 used.  

 The reason what you have cabled works is because of vertical failover on the controllers.  Since controllers on the Dell PS Series don't failover on loss of network.  And without MPIO a NIC or cable failure where the 12v link is maintained would be the data would stop so no 'failover' would occur in that case. 

 Regards, 

Don

 

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pidyna.v
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Re: Which RAID level for virtual machines in EqualLogic 5000

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Ok, and please one question else. Can i use not dedicated switch for this task. I mean, that i will use switch from my server room, but all these ports (from these DELL r620 and from this SAN), i will connect to dedicated VLAN.
I mean, that all ports of this switch will connect to my other servers, but several ports i will use for SAN and these DELL r620 with using of dedicated VLAN

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dwilliam62
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Re: Which RAID level for virtual machines in EqualLogic 5000

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Hello, 

 Yes you can use a separate VLAN on an existing switch assuming it has sufficient specifications for iSCSI use. 

Given how small the environment I suspect you will be OK.   Just make sure the ports are UNTAGGED, jumbo frames, Flowcontrol enabled, and portfast (aka PVST) is enabled on all server and EQL ports. 

 Regards,

Don

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