Too old for ZFS?; suggestions on disk config

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hotcrandel

Gawd
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Feb 26, 2010
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I've got some older but still use able servers on the shelf at work I want to make available for ESXi capacity.
I've been happy with some of my latest builds but these last few servers I have aren't necessarily ideal for all-in-one due to various factors.

This thread pertains to disk configuration; read on for background.

I've got four different 1u supermicro server;

(2) dual core2 quad xeons, 16GB ECCram, redundant PS, quad-hot-swap ultra 320 disks
(2) single core2duo xeon (3040 1.86ghz), 8GB ECC, dual hot-swap SATA

Was thinking about making the 2-bay SATA servers into data store with either a pair of 1TB velociraptor, or 2-3TB 7200RPM, then maybe ZIL or zARC sata disk fastened in a PCI slot.

Planning on running 16-32GB of low usage VM's per server

Asking for opinions between

zfs/R1 1TB velociraptors without ZIL,

vs

2/3/4TB 7200RPM disks with ZIL, at about the same upgrade cost ($500?) or so per server.

Also; Am I making a mistake trying to do ZFS on a 1.86ghz dual core with only 8GB RAM?

I've got a server with 6x2TB disks that i'm pretty underwhelmed with the freeNAS performance. no ZIL, 16GB RAM, etc. iSCSI might also be the issue as well. Lots of latency reported by ESXi, and its felt pretty readily in the guests.

Edit; not sure if ICH7R supports 4TB disks. You would like to think it could..
 
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Keep in mind too that the memory guidelines are mostly for if you read cache. If your use case is for, say, streaming media or some such, 8GB is fine (hell 4GB is fine...)
 
Liggywuh said:
Only thing I can chip in here is that normally people say 1GB of RAM per 1TB of storage.
Click to expand...
This is only true if you use ZFS deduplication. You should not use ZFS dedupe because the implementation is immature. So, 2GB RAM suffices. If you have more RAM, then ZFS will active a very efficient disk cache. But disk cache is not needed.

I ran ZFS on an OpenSolaris PC with 1GB RAM and four disks in a raidz1 for a year, without problems. It was slow because I used a Pentium4 which is a 32bit cpu. ZFS is 128 bits, so you need 64 bit cpu for full read/write speed.
 
I'm running another server with dual xeon dual core core2 chips and 16gb memory, and the performance (due to latency) is very poor on the server with the number of VM's I'm running on it (over a single gig line).

(maybe 8 vm's running web/ftp/file servers)

was trying to do a bit better with the next one, so was wondering if the ssd cache will help a lot, or doing NFS instead of iSCSI will help.
 
My server is running FreeBSD with an AMD Regor 250 and 4GB RAM. It is only a file server, and runs fine. I'd like to get more RAM, but can't justify the cost of DDR2 ECC on an old system.

I'm only running 4 drives, two mirrored pairs, but don't think I'd have any problem running a larger array (and will need to at some point).
 
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