Home virtualization and IOPS requirements

[blinkenflamingo]

I'm in the process of creating a diskless ESXi 5 server for general testing, fiddling around and VCP studying at home but I'm not sure if my NAS box (i will provision storage to the ESX box from there) can cope with the requirements.

NAS box specs:
- Athlon 64 X2 4000+
- 4GB ram
- 3x2TB Samsung HD204UI in mdadm Raid 5 + 1 hot spare
- Quick 'n dirty calculus tells me 200/50 IOPS Read/Write

What the ESX box will probably run:
- Webserver
- Rendering VM with backburner for my brothers 3DS "rendering takes years" MAX.
- A few Windows Server 08 VM's to test stuff
- Maybe an Avamar Virtual Edition for testing and Avamar Specialist track.

The big question: will my NAS box be able to serve the needed IOPS (Avamar VE is already going to be TIGHT) for simultaneous file serving and VM work? I'm afraid my general file serving will get nuked by the backburner VM. Bandwidth wise I'm going with a direct connect GigE to separate VM and file traffic.

Any people with experience on this issue?
People who can tell me where and why my idea will fail are also welcome .

 

[CEpeep]

I don't think you have anything to worry about. We were using a 1st-gen Atom system as the ZFS NAS for half a dozen hosts (~100 guests) and it worked ok before we upgraded everything.

 

[Child of Wonder]

It'll probably run really slow. A trio of green hard drives in RAID 5 will crawl when you write to them.

Hard drive prices make this difficult, but I'd recommend a separate RAID 5 or even RAID 10 array just for the VMs. My ZFS file server at home runs 8x500GB 7200RPM drives in mirrored vdevs (RAID 10) and it screams. I routinely run 10+ VMs on there without a problem.

 

[danswartz]

Child, what arc cache rate are you getting? I have a 3x2 wd blue array on my all in one with 9 or so VMs and it works very well. arc_summary.pl shows 77% real cache hit rate with 6GB assigned to the SAN VM.

 

[Child of Wonder]

Child, what arc cache rate are you getting? I have a 3x2 wd blue array on my all in one with 9 or so VMs and it works very well. arc_summary.pl shows 77% real cache hit rate with 6GB assigned to the SAN VM.

Here's what Napp-It tells me.

System Memory:
Physical RAM: 16118 MB
Free Memory : 2403 MB
LotsFree: 251 MB

ZFS Tunables (/etc/system):

ARC Size:
Current Size: 11957 MB (arcsize)
Target Size (Adaptive): 11957 MB (c)
Min Size (Hard Limit): 1886 MB (zfs_arc_min)
Max Size (Hard Limit): 15094 MB (zfs_arc_max)

ARC Size Breakdown:
Most Recently Used Cache Size: 91% 10924 MB (p)
Most Frequently Used Cache Size: 8% 1032 MB (c-p)

ARC Efficency:
Cache Access Total: 601350388
Cache Hit Ratio: 92% 556704998 [Defined State for buffer]
Cache Miss Ratio: 7% 44645390 [Undefined State for Buffer]
REAL Hit Ratio: 63% 381632984 [MRU/MFU Hits Only]

Data Demand Efficiency: 90%
Data Prefetch Efficiency: 75%

CACHE HITS BY CACHE LIST:
Anon: 30% 169365862 [ New Customer, First Cache Hit ]
Most Recently Used: 12% 69331644 (mru) [ Return Customer ]
Most Frequently Used: 56% 312301340 (mfu) [ Frequent Customer ]
Most Recently Used Ghost: 0% 1718244 (mru_ghost) [ Return Customer Evicted, Now Back ]
Most Frequently Used Ghost: 0% 3987908 (mfu_ghost) [ Frequent Customer Evicted, Now Back ]
CACHE HITS BY DATA TYPE:
Demand Data: 30% 170921324
Prefetch Data: 13% 75507390
Demand Metadata: 37% 210711397
Prefetch Metadata: 17% 99564887
CACHE MISSES BY DATA TYPE:
Demand Data: 38% 16969950
Prefetch Data: 55% 24615711
Demand Metadata: 3% 1783638
Prefetch Metadata: 2% 1276091

 

[danswartz]

Nice...

 

[blinkenflamingo]

Cheers for the info. I'm going to wing it with what I have and see what the setup does under stress. I thought of moving the Hot Spare to the array as a data disk but with Raid 5 and the high HDD prices I'd rather have something for windy days.

I'm thinking of some ebay'ed SAS disks if the Samsung array doesn't cut it. I noticed 73GB 10K drives aren't that expensive and they pack a lot more speed than usual disks.

 

[danswartz]

Mine:

System Memory:
Physical RAM: 6135 MB
Free Memory : 788 MB
LotsFree: 95 MB

ZFS Tunables (/etc/system):

ARC Size:
Current Size: 4268 MB (arcsize)
Target Size (Adaptive): 4268 MB (c)
Min Size (Hard Limit): 638 MB (zfs_arc_min)
Max Size (Hard Limit): 5111 MB (zfs_arc_max)

ARC Size Breakdown:
Most Recently Used Cache Size: 74% 3184 MB (p)
Most Frequently Used Cache Size: 25% 1084 MB (c-p)

ARC Efficency:
Cache Access Total: 67499026
Cache Hit Ratio: 92% 62290902 [Defined State for buffer]
Cache Miss Ratio: 7% 5208124 [Undefined State for Buffer]
REAL Hit Ratio: 78% 52932406 [MRU/MFU Hits Only]

Data Demand Efficiency: 93%
Data Prefetch Efficiency: 37%

CACHE HITS BY CACHE LIST:
Anon: 13% 8171843 [ New Customer, First Cache Hit ]
Most Recently Used: 29% 18543297 (mru) [ Return Customer ]
Most Frequently Used: 55% 34389109 (mfu) [ Frequent Customer ]
Most Recently Used Ghost: 0% 146406 (mru_ghost) [ Return Customer Evicted, Now Back ]
Most Frequently Used Ghost: 1% 1040247 (mfu_ghost) [ Frequent Customer Evicted, Now Back ]
CACHE HITS BY DATA TYPE:
Demand Data: 58% 36389715
Prefetch Data: 1% 1231645
Demand Metadata: 26% 16470655
Prefetch Metadata: 13% 8198887
CACHE MISSES BY DATA TYPE:
Demand Data: 45% 2379898
Prefetch Data: 38% 2020274
Demand Metadata: 11% 607790
Prefetch Metadata: 3% 200162