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i recently had a phone interview, and did not get the job. i'm curious if i didn't get the technical questions correct, or whether there was something else about my interview that caused me to not get the job. how would you answer these questions:

what RAID array(s) would you recommend for a read/write intensive database on NAS?

what would you do to ensure network availability?

devlin carnate
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    Please read the FAQ ("help" link at the top). You're asking a good question, but it's not a good one for this site. – mfinni Jun 19 '13 at 20:07
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    Also : https://lopsa.org/mentor/WhyProtege might be a good place to get some help with your career, if you're new at systems administration. – mfinni Jun 19 '13 at 20:07

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Please note that this is off-topic here, but it's always a bummer when you don't get a job. I've answered to throw you a bone, but PLEASE read through our help center before you ask another question.

what RAID array(s) would you recommend for a read/write intensive database on NAS?

If you have sufficient write cache, then any RAID level will be fine. If you're assuming a condition with no write cache, then any RAID level without parity is preferred (RAID 1, RAID 10)

what would you do to ensure network availability?

This is clearly an open-ended question with no right answer. It's meant to gauge your knowledge of networking protocols and design. There's no "right" answer to this, there's only what you know.

Things that they might be expecting you to talk about are: redundancy in a core switch (multiple supervisor blades), redundancy across core devices (OSPF, VRRP, etc), physical design like having redundant fiber into the building from opposite sides of the road. They might even want to hear about datacenter availability, like redundant UPS units and placing redundant network cores on different legs of different UPS units.

Again, there's no "faking" an answer to this question. Either you know it and have a good answer or you don't. They'll be able to tell, don't BS if you don't know.

Community
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MDMarra
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  • For what it's worth my answer to question #1 would be "I would not recommend using a NAS for a database server - If local disk doesn't make sense I'd go with a proper SAN tuned appropriately with an adequate cache and fast backing drives. Probably RAID 1 or 10 but it depends on the database's disk access profile". – voretaq7 Jun 19 '13 at 20:13
  • @voretaq7 it depends on the shop. If I'm not mistaken, Oracle DB **loves** NetApp (and now the Oracle storage appliances) over NFS. MSSQL Server 2012 also supports databases hosted in SMB. It's a brave new world we live in. – MDMarra Jun 19 '13 at 20:14
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    Oh brave new world that has such saturated switching backplanes in it... EVERYBODY STOP LOOKING AT CAT VIDEOS! I NEED TO RUN A REPORTING QUERY! (of course if you stick your NAS on its own network --- but now we're just talking a SAN again :-) – voretaq7 Jun 19 '13 at 20:31
  • We run an Oracle Real Application Cluster on NFS. It works shockingly well. For what little you lose in performance, you gain in massively easier administration. No more WWNs, HBAs, compatibility matrices, drivers, etc. And it's infinitely easier to grow/shrink volumes. That being said, we do give it its own network...but that doesn't quite make it a SAN. – Christopher Karel Jun 19 '13 at 21:25
  • @voretaq7 `(of course if you stick your NAS on its own network --- but now we're just talking a SAN again :-)` By the strictest definition of "Storage Area Network," sure. But generally (and colloquially) SAN is block, NAS is file. :p – MDMarra Jun 19 '13 at 22:31