IT question about disc arrays and RAID

[drift_g35]

I am starting to become more of a productive role with my company, working towards being a DB Admin. I asked about a month ago what you suggested the next step be and someone mentions that keeping up to date of arrays was very important. Unaware at how much a whole set up cost I asked my CEO if I could borrow one to play with and learn how they work (I dont know much about them). He laughed and said that our array setup cost about $100,000 with a controller and everything.

So... What I need to know is what less expensive ways can I get some training on this stuff. I was looking online but I dont even know where to start. Does anyone have any suggestions?

Thanks!

[Gman]

You don't need one to learn about them. Most of what you need to know is high-level as to the pro's and con's; how much storage is lost to have redundancy (RAID 1 = 50% vs. RAID5 = 1 disk, etc.), % of reads vs. writes, rebuild times for failed disks, etc.

The management tools for an array will likely change depending on if it's internal storage vs. an external array.

Some basics can be performed with a desktop that has a controller. I have a home server that backs up all of my systems, so I'm not concerned so much about data retention. I used to run HDDs in a RAID 0 configuration for the extra performance, but SSD has made that unnecessary.

[DOC]

3.5" diskettes all the way.

[esaabye]

For DBA's it is all about IOPS which is a function of the disk speed and the number of them in an aggregate. In the old days we would spend lots of time breaking the BD into table groups and speading across different disk types based on performance needs.

Now we buy an san with data progression and let the controllers move blocks around so that the more popular data is on the outside enge of the fastest spindles. Now we are starting to get SSD and large flash arrays with tons of caching at 'reasonable' pricing thus further removing the planning needs.

Take a look at some of the larger san provider sites (EMC, Dell, HP) and some of the niche like Nimble and read the cool-aid. They will all spin it differently but in the end it is a function of speed of disk times number of disk.

[Holger Danske]

Learn the RAID levels and pros/cons. Agree with Essabye it is about IOPs (and latency). You can buy little 4 disk JBOD's with RAID built in for a couple hundred bucks. Also, my buddy was telling me about unraid. They make arrays and offer a free raid sw solution. I have not checked them out, but you may want to look into it if you want a cheap way to learn. If you have any DBA's or Network admins that have been around the block then pick their brains.

[mitch]

One small nit: if you have a raid controller in front of your disks, you can't specify where your data goes at a granularity smaller than the LUN. The old "outside of the spindle" tricks haven't been valid for a number of years. It's still the way to go for making linux raid devices from a bunch of internal disks, though. Google "linux" and "raid" and you should get the software raid how-to. If you have a spare disk you can wipe - there's no reason you can't partition it into 4 or 5 partitions and mirror them to themselves just as a means of learning some of the commands.

Otherwise, this is an exciting time to be in storage. You can now get 100k IOPS on your desktop quite easily with some of the various flash units out there today. I know there are various companies producing well over 1M I/O per second sustained at fiber speed (in this case, newish 8Gb stuff from Qlogic).

If you want something to play around with at home, some of the various projects like OpenFiler and the like are pretty slick. In general it's like horsepower. Sure you can "do raid". How much money do you have?

[ChadAmberg]

If you REALLY want to spend a few bucks and get something to play with, look on Ebay for an older HP or Dell server with a raid controller and at least 4 disks. Probably get it for a couple hundred bucks. With the 4 disk, you can experience RAID 0, 1, and 5 in both 3 and 4 disk configurations.

[drift_g35]

Thanks for all the info. I'm not looking to spend a whole bunch of money. I also have no experience with anything outside of some basic to intermediate IT skills. I'm a software developer currently but the DB side of things are way more interesting to me. I am currently taking a SQL Server class to get the Microsoft certification. I am doing this because its the only way I could get my work to pay for it since we use SQL Server. I am mainly trying to get as much information as I can to do the research. I also want something to play around with that isnt going to cost a fortune and that I can actually take advantage of as a home server or something.

If there are any books that you recommend or really anything you have to offer is greatly appreciated. Thank you![Beer]

[Circuits]

The biggest thing with RAID these days is that the capacity is so large, even with hot spares and hotswap, it can take longer to rebuild around a failed disk within a volume than mtbf to the next disk failure. For large arrays you need serious cooling and environment controls to promote the longevity of your unit drives, and a heavy-duty hardware based controller to speed up the writing and rebuilding.

Learning the concepts is relatively easy from whitepapers and wikis available on the web. Specifics of management, performance of hardware and such, will take a lot of familiarization, tinkering and comparison shopping.

[scratchy]

I work for Oracle in storage engineering, I'd be happy to give you a tour and answer questions. Your questions
have complex answers but can be simplified into easy solutions. Shoot me a PM and we can have a tour and QA
session over lunch or beers. Beers preferable

[Ashton]

http://ocw.mit.edu/courses/

[cfortune]

I work for Oracle in storage engineering, I'd be happy to give you a tour and answer questions. Your questions
have complex answers but can be simplified into easy solutions. Shoot me a PM and we can have a tour and QA
session over lunch or beers. Beers preferable

You should come over and optimize our Oracle RAC cluster's storage. We have kegs at work [Beer]

[james_bond_007]

What these guys said ^^^^^^
and get somewhat familiar with the hardware architecture...

If you will be working with enterprise systems, learn the differences of SAS and SATA, what an SAS Expander is and does, backup strategies and schedules, practice actually restoring data (you won't believe how many people religiously backup data, only to find, after a crash when they go to restore, that NOTHING was ever backed u), hot spares and how to use them, fault tolerances of the various RAID protocols, why S/W RAID is a poor performer, other systems than RAID (ex. Just A Bunch of Disks JBOD), their tradeoffs with RAID (speed/fault tolerance/storage-to-media ratios), what are volumes/spanned volumes, how to increase a volume by adding more disks, etc. ,

Enterprise is all about spending extra $$$ for
1) Preventing downtime
2) Not/Never losing data...at all...even if a user deletes it, you need to be able to recover it (within a reasonable time frame...ymmv)
3) How to get back up as quickly as possible after a crash

[Ashton]

You should come over and optimize our Oracle RAC cluster's storage. We have kegs at work [Beer]

The last company I worked for had "beer fridays" with kegs... They got rid of them when the sales people (me) started being honest because we were drunk.

[Ashton]

What these guys said ^^^^^^
and get somewhat familiar with the hardware architecture...

If you will be working with enterprise systems, learn the differences of SAS and SATA, what an SAS Expander is and does, backup strategies and schedules, practice actually restoring data (you won't believe how many people religiously backup data, only to find, after a crash when they go to restore, that NOTHING was ever backed u), hot spares and how to use them, fault tolerances of the various RAID protocols, why S/W RAID is a poor performer, other systems than RAID (ex. Just A Bunch of Disks JBOD), their tradeoffs with RAID (speed/fault tolerance/storage-to-media ratios), what are volumes/spanned volumes, how to increase a volume by adding more disks, etc. ,

Enterprise is all about spending extra $$$ for
1) Preventing downtime
2) Not/Never losing data...at all...even if a user deletes it, you need to be able to recover it (within a reasonable time frame...ymmv)
3) How to get back up as quickly as possible after a crash


Define "enterprise"... In my experience it's 2500+ seats. Which makes everything you said correct and applicable. But no 2500+ seat company is going to hire someone for a DBA that doesn't know anything about RAID configurations. For the jobs he could get (without the knowledge) none of those are applicable. Because they can't afford it.

[cfortune]

The last company I worked for had "beer fridays" with kegs... They got rid of them when the sales people (me) started being honest because we were drunk.

Yeah, I won't have more than a single beer at work for that very reason. We have people who have kegerators in their cubes.


Define "enterprise"... In my experience it's 2500+ seats. Which makes everything you said correct and applicable. But no 2500+ seat company is going to hire someone for a DBA that doesn't know anything about RAID configurations. For the jobs he could get (without the knowledge) none of those are applicable. Because they can't afford it.

Not true at all. We only have around 200 employees and we have two DBA's, five systems engineers (these guys do our Windows, Linux, backup and VMware), two network engineers (that's what I do), two systems administrators, and two automation engineers. We're currently taking applications for a storage engineer that also has heavy Linux experience as our last one was promoted to be our manager. We have far more terabytes of data than we do people (over 500 if I recall correctly, 3 NetApp systems, two BlueArc NAS/iSCSI systems, and a smaller Hitachi system for disk backup). Our DBA's don't touch our system builds nor our storage appliances.

[scratchy]

Do we get to work on RAC after the beers? I'm working for the wrong company ! [Beer]

[drift_g35]

http://ocw.mit.edu/courses/

Any suggestions as to which class to take? I see a bunch of stuff with would be WAY over my head. But that is great. I was not aware that MIT had so many classes to offer. I usually look at Coursera for classes but they dont have every class apparently.

[ChadAmberg]

Are you looking to be a DBA or a database developer? There is a big difference in what they do, even though most folks think the two jobs are the same.

[drift_g35]

Are you looking to be a DBA or a database developer? There is a big difference in what they do, even though most folks think the two jobs are the same.

I would like to expand my knowledge in both areas. I am currently working on my MCTS70-432 and 70-433 which would be (DBA 70-432 and Developer 70-433) My company currently doesnt have anyone who is either. We have people that know what they are doing but they dont do that constantly. I am trying to create a position for myself. My company takes really good care of me and I am very motivated to become a much larger part within.

Basically what I am saying is I am willing to take what is thrown at me. I enjoy writing complex queries more than administration. I have always been willing to do "bitch" work because I have always learned something from doing stuff other people dont like doing. Thats usually why its concidered bitch work because they arent very familiar with it.

[th3w01f]

If you have an older PC or Laptop that you're not using you can load FreeNAS on it and get a bit of experience.

http://www.freenas.org/

I had a Lenovo with a couple of external USB drives attached running as a NAS for a while and it worked well.

NetApp also has a simulator you can download to get some experience with their frontend. This is all more towards the storage side rather than DBA side but it's pretty easy to learn the basics.

[mitch]

You probably won't like to hear this, but Enterprise customers seldom use Microsoft for their back end. It's very rare when one considers the current installed base size - typically Windows is the desktop and desktop services applications. The back end systems will be mostly HPUX, Solaris, AIX, and Linux, with Linux predicted to be the dominant enterprise OS in the very near future (say, maybe 2 lease refresh cycles aka 6-8 years).

You should get a linux box or two up and running as soon as possible. Stick MySQL (if you want to work on web stuff) or PostgreSql (compatible with Oracle scripting) on there and get to churning out some configurations. Neither of these will get you experience with things like HANA, but it will enable you to speak and think intelligently about the stack when you meet it in the real world.

[Gman]

Enterprises do use SQL in addition to Oracle, DB2, etc. We're a Fortune 200 and we have more SQL DBs than Oracle or the others combined. SQL is a good product and is quite robust and flexible. We use it in some pretty impressive ways. SQL has powered the NASDAQ for quite some time. http://www.microsoft.com/en-us/sqlserver/product-info/case-studies.aspx

I've been hearing about Linux taking over the world since the 90s. HP is driving their proprietary high-availability features into Windows and Linux, so don't expect HP-UX to be out there for more than about 5 years or so. Oracle doesn't seem to know what they're going to do with Solaris. IBM is expensive, so I've encountered more limited use of AIX/DB2.

[ChadAmberg]

Enterprises do use SQL in addition to Oracle, DB2, etc. We're a Fortune 200 and we have more SQL DBs than Oracle or the others combined. SQL is a good product and is quite robust and flexible. We use it in some pretty impressive ways. SQL has powered the NASDAQ for quite some time. http://www.microsoft.com/en-us/sqlserver/product-info/case-studies.aspx

I've been hearing about Linux taking over the world since the 90s. HP is driving their proprietary high-availability features into Windows and Linux, so don't expect HP-UX to be out there for more than about 5 years or so. Oracle doesn't seem to know what they're going to do with Solaris. IBM is expensive, so I've encountered more limited use of AIX/DB2.


Agreed. My company is in the Fortune 15 and we've got every kind of sql imaginable out there. DB2, MSSQL, SQL Anywhere, Oracle, open source DBs, etc. I talked to one of the folks in our centralized DB group and there are THOUSANDS of sql server databases he's responsible for. And that's just the centralized group, my current projects aren't in that group, and I've got probably 10-15 MSSQL databases in our environment.

What you'll find as you get deeper into bigger enterprises is the less you need to know. At your level, you'll probably specify and configure the hardware which is what you're learning to use. When you get to bigger companies, you'll tell the SAN folks you are hooking a DB server into their SAN and they'll know what to do. Past that, you'll request a DB from a big group of folks who just run and manage giant SQL cluster farms.

[drift_g35]

So what you are saying is I need to learn a lot about a lot and not focus on just one thing?

[ChadAmberg]

At this state of your career, I'd say becoming a dba/sqldev is a good choice. You'll need to know basic Windows administration.
Most importantly: LEARN ABOUT PERFORMANCE MONITORING!!! I can't stress this enough. Probably only about 2% of sysadmins know about the correct use of perfmon and other tools. Learn it, live it, love it. It is the difference between a good admin and a great one. You can troubleshoot weird issues about 20x faster if you know tools like this.
You're also on the right track about learning about RAID and disk performance. All about spindles, LUNs, etc. Soak up that knowledge. Buy the SAN guys donuts for them to show you how and why they set up LUNs and RAID groups for your servers.
Then definitely keep going down the track of the certifications for SQL.

[james_bond_007]

Define "enterprise"... In my experience it's 2500+ seats. Which makes everything you said correct and applicable. But no 2500+ seat company is going to hire someone for a DBA that doesn't know anything about RAID configurations. For the jobs he could get (without the knowledge) none of those are applicable. Because they can't afford it.

I've seen enterprise used in 2 ways:
1) # of users (similar to what you describe) and
2) Style or class of data management - smaller companies often use more sophisticated/robust methods, if they or their customers are in a position to pay to offset the expense. I have seen this with smaller financial clients, government contractors managing sensitive data, clients that are may be audited by various private/government agencies

What I was trying to imply was the he should get familiar with the pros/cons (I.E "LEARN ABOUT") of different approaches, but not that he become an expert at this point. Learning about the higher end stuff will allow him to better understand 1) What CAN be done, if needed and 2) What the trade-offs are by NOT doing them.

About the only thing I recommended him to do is to restore things once in a while, to make ABSOLUTELY sure things are being backed up as planned.

I was also generalizing...I don't know what type of Job he is after at this point.

Reading through some more, I would also say that learning to use/program SQL would be a useful skill, in all cases.

[drift_g35]

At this state of your career, I'd say becoming a dba/sqldev is a good choice. You'll need to know basic Windows administration.
Most importantly: LEARN ABOUT PERFORMANCE MONITORING!!! I can't stress this enough. Probably only about 2% of sysadmins know about the correct use of perfmon and other tools. Learn it, live it, love it. It is the difference between a good admin and a great one. You can troubleshoot weird issues about 20x faster if you know tools like this.
You're also on the right track about learning about RAID and disk performance. All about spindles, LUNs, etc. Soak up that knowledge. Buy the SAN guys donuts for them to show you how and why they set up LUNs and RAID groups for your servers.
Then definitely keep going down the track of the certifications for SQL.

Unfortunately I am at a satelite office with only developers and QA. So the guy that sets up the stuff isnt easily accessable nor would he be excited about me asking him questsions... He's quite the [ahole] . Which is why i'm asking here. I can offer free beer for specific training though! [Beer]

[ChadAmberg]

Unfortunately I am at a satelite office with only developers and QA. So the guy that sets up the stuff isnt easily accessable nor would he be excited about me asking him questsions... He's quite the [ahole] . Which is why i'm asking here. I can offer free beer for specific training though! [Beer]

Hehheh... I think that generally comes with being a SAN guy. Not sure why...

Well, keep going down your path and add performance testing/monitoring as a secondary thing for you to learn. I'm sure some of us would be able to share some SAN/DASD/Disk/LUN knowledge with you.

[buckshotbarlow]

ok, so you want to learn raid...first figure out market share...then hit the websites and search for their tuning docs.
netapp has a simulator that you can use...remember that lsi was bought out by netapp so the old lsi interface is going bye bye...
emc might have a simulator, i just refuse to work on it after dealing with a 33PB setup...i think their stuff is garbage.
hitachi has some kewl stuff, you'd have to google to see if they have a simulator.
IBM has/is trying to standardize their interface. They do have a simulator. But they have a gazillion vidz on youtube. Start with the v7000 and SanVolumeController (SVC). The sim is for the lower end stuff...ds3xxx to midrange ds53xx.
DDN has some really kewl stuff, but they don't have the market share.

Ebay is the right answer, but make sure that you have the power to drive the older stuff. You'll need at least 1 20amp circuit. Tuning storage and optimizing IO to the disk array is where you'll make your money...