NovaTC

What is the best cheap RAID5 solution?

Recommended Posts

Promise supports data migration, how does it do that? In fact, how can any card support migration when the data never leaves that original raid 5 to begin with. I know that there are card that can add to or take away from the raid 5, but migration; i am very unclear on this matter!

SCSA

Share this post


Link to post
Share on other sites

I find it not too hard to imagine how data migration might work. For example, when going from a basic 2-disc RAID0 stripe set to RAID 5, e.g. by adding one disk, all that has to be done is moving one third of the data from the two existing disks to the new disk while at the same time using the now free space on the two "old" drives for parity info. From a RAID 1 to RAID 5 is comparable, just move some data to the new drive, add the parity information to the two old ones.

You can do it in such a way that even a hard shut down (i.e. power switch or black out) won't compromise RAID integrity, you just have to be sure that the data is always stored somewhere, plus information about the current state of RAID level migration, so that the controller knows what it was doing last and where it has to continue migration.

Removing disks is another matter. When going from 3-disk RAID5 to three -disk RAID0, you simply drop the parity info. When going two two-disk RAID-0 you have to empty one drive, by successively removing parity information on the two remaining drives and replacing data. You would hardly need any free space to do this. Perhaps some sectors reserved for RAID metadata will be sufficient (but more free space will likely migration faster) . Of course you will loose RAID5 benefits immediately after you start the migration.

Whenever a migration reduces the capacity of the array, you will need to provide enough free space on the disks (and perhaps do a defragmentation and free-space consolidation on the file system level). Yet here I wonder, how the RAID controller (who should not have any idea about the filesystem on the RAID) knows which sectors of the array are empty. Any ideas?

Share this post


Link to post
Share on other sites
Did you ever try running your setup with Linux?

No, and I am not planning to in the future, that is why I guess I am not so "hostile" towards considering (and purchasing) Promise RAID cards. I have been pretty much using DOS/Windows 3.1/3.11/NT 4.0 Workstation & Server/Windows 95/95 OSR2/98/98SE/Me/2000 Professional/XP/2003 Server over my entire computing experience so far.

My University's Engineering Department uses Linux and I have (more like semi-forced) to use it for 3 years, and I am indifferent to it. However I don't think I will consider running it at home for anytime soon.

So, I could understand why people prefer 3Ware/LSI etc.. as they have better Linux support.

I have yet to try Array Migration on ANY RAID arrays, since I never considered RAID 0 and RAID 1 simply "costs" too much in disc space. Array Expansion (Online Capacity Expansion) is the only other major RAID feature I used (and it is a no-brainer how it works anyway).

Share this post


Link to post
Share on other sites
Another way of looking at it is "sure a BMW or Merc is going to be nice, best performance and highsafety ratings, but can I afford one? No, a Honda is just going to do the same job - probabally have similar features and performance, but at a cheaper price. So is there really any reasons to NOT even consider the Honda? In my opinion, no."

You were doing ok until you hit the part I emphasized up there. Don't forget, TANSTAAFL!

If you had said "A Honda will have all the features that are important to me and I'm not all that concerned with performance," I would have agreed with you.

There is no one in the world that is going to take a $10 bill and sell it to you for $5. It just doesn't happen. Hondas that have similar features and performance to BMWs and Mercs cost about the same as they do.

-- Rick

Share this post


Link to post
Share on other sites

lol, from where I live (New Zealand), the most expensive Honda Accord model (well here it would be the Honda Accord V6-L Mugen) + full options costs a maximum of NZ$52000 (Price from Honda NZ)

A similar classed BMW, lets say the 5-series 525i, standard specs (no extra options), STARTS at NZ$98000

Even if I were to drop down to the 3-series, the cheapest one, 318i sedan, bare standard no options, STARTS at NZ$65900 (All prices from the official NZ BMW site)

In no way can I afford a BMW... (and for your information I did purchase a new Honda Accord V6 recently, not the top model tho..)

That's where I got the analogy from when comparing the different classed RAID cards.

Granted the BMW is still going to nicer... but the Honda has almost the same basic specs, same performance, same comfort level etc.. (I test driven both).

P.S.: Although I have heard from a few friends in the States that Honda sells for nearly the same price as a BMW due to import tariffs etc.. Well at least down here where I live Japanese cars are WAY cheaper than similar European counterparts in the same class level.

Share this post


Link to post
Share on other sites

Hi NovaTC,

i was considering getting a raid 5 setup as well. One of my big 250 gb drives was failing so it had to be done. Cost was a big factor for me as well.

In the end i took a old p2 350 and got a highpoint 1820a raid controller.

Bought 5 seagates 200gb drives and put the computer in another room.

I know the setup isnt optimal but this way if i upgrade my main machine ( which might be soon) the current motherboard goes into the server .

At the moment i get about 30mb/s over my gigabit network from the server.

For normal operation thats plenty and it has the potential of getting faster without investing extra money.

Share this post


Link to post
Share on other sites
Although I have heard from a few friends in the States that Honda sells for nearly the same price as a BMW due to import tariffs etc.. Well at least down here where I live Japanese cars are WAY cheaper than similar European counterparts in the same class level.

Actually, the most expensive Honda's here in the US are (at least partially) built here, and badged as "Acura." And they cost about the same as the European sports sedans.

But even down under, I'm betting that if the Japanese cars are less expensive than the Europeans, that there is a certain cachet associated with the BMWs and Mercs that you just don't get with a Honda.

--Rick

Share this post


Link to post
Share on other sites

Ive got a Promise S150 SX4 sata raid card and just want to share with you guys my experience and times with it.

Ive got sx 4 in a raid 5 array and it works good only some minor complaints with it. It would not work with my Gigabyte Nforce3 250 GB mobo ( iforget the exact model, but it has nvidia ata raid, ite ide raid, and a sil sata raid onboard). I tried all manner of things, different slots, different configurations, updated raid and mobo bios but could not get it to work. It would hard lock trying to install xp right at setup is inspecting your hardware configuration. Promise's support was less than helpful. I was trying to setup my system for os to boot on wd740 on nvidia sata and the sx4 just for data. Promise suggested using it as the boot os. As it would lock up trying to install, it was no go either.

My roommate had just gotten the MSI K8 Neo Platnium (same chipset, no ite ide raid) and I tested and it worked fine on it, even allowed me to use the integrated sil sata raid controller or a pci sil sata raid controller without conflict. I decided to go ahead and build a dedicated file server with the card and bought a supermicro p4sca+II mobo. The mobo has a 4 port marvel sataII controller with ncq support using an adaptec firmware/driver/software. I was really hoping to use those ports but alas if the promise card is installed (and the marvel/adaptec sata raid enabled) the system locks up on the adaptec bios, very disappointing.

I started the array with 3 maxtor 200gb hdds in raid 5. The price per gb on the 200s overall was best and it looks like 250s have a slightly higher failure rate (no concrete data, just something ive noticed). After moving data off the other sources to the array. Added a 4th maxtor 200gb hdd and did the online capacity expansion. Worked well, only drawback is partitioning. WIth xp pro it just adds the new space as unpartitioned space and you have to create a new partition and format it (giving you two, partitions). Possibly converting it to dynamic would allow the expansion to work as just one partition. But several forums and friends advised against it, especially as there was no backup of the data thats on the array. So now i have a 400gb and a 200gb partition setup raid 5.

The promise card has DRM (Drive Roaming Metadata) technology which seems like a really cool technology. the main point I liked with DRM is the ability to upgrade any Promise storage sub-subsystem. My plan is when the 8port sataII controller becomes availble in the us. to get that card, migrate my current array to it (hopefully without issue). Then create a second raid5 array using 3 of the maxtor maxline3 sataII w/16mb cache drives. I currently have 2 of the maxlines as os and temp data storage.

I have reservations about the promise card from the nusances and incompatibilities ive had with it, but overall its a good card and peforms well. It benchmarked really good in the fileserver benchmarks for entry level raid 5 cards ive seen. The card was 170 from zipzoomfly.com and the hdds were 130ish a piece, so bout 700bux for 600gbs of hardware raid 5. not bad, about $1.16 per gig is what I paid. The price has come down on the drives since then so it makes it about $1.04 per gig. Who can argue with about a buk a gig!!

In one stress test session the system serverd over 840 gigs of data in less than 24hrs using 100mbs nics without a hickup. Id say do some research, check the manufacturers documentation, compatability list and any forums/newsgroups you can think of. If ya board is not on there list, it may not work right, or may work but cause something else not to work.

-mo

Share this post


Link to post
Share on other sites

@mohawk: What you report worries me a little. I did not expect stellar support from a budget label, but still... . I hope the nForce3 problem you report does not translate to some nForce2 boards as well. You mention a conflict with the onboard serial ATA controller on the Supermicro board. How did you solve it? Did you disable the onboard controller or did you find a workaround?

About RAID expansion... you might be able to increase the size of the existing partition with a tool like partition magic (which, at least in the last version I remember did most of the dirty work under plain old DOS, so you are probably out of luck if Promise does not supply DOS drivers for the card. But it might work under Windows as well, I always used it on a bare system without a functional OS.) Linux offers tools with a similar functionality, but I never used them. Of course, using any such tool means putting your data at jeopardy. I used PM to do some minor partition modifications (on an unRAIDed disk connected to an onboard controller), I had no problems but your mileage might vary.

@VDPloeg

Thanks, the reviews are interesting.

As you can guess, I still have not purchased anythign RAIDish. I am no easy customer, and since my vacation is over, I might as well wait for a native card by promise (i.e. SX4 successor).

Share this post


Link to post
Share on other sites
I was going to buy a 3Ware or LSI Logic SATA RAID card ... BUT... their prices are too steep for me to justify buying them.

Apple introduced a whole slew of new products today, and dropped prices on a bunch more. Now they're touting their incredibly affordable RAID system:

"Finally, Apple revamped its Xserve RAID rack-mounted storage system. The new Xserve RAID systems come in three models. The first features four 250GB modules and sells for $5,999. "

Makes 3Ware and LSI Logic look absolutely cheap, doesn't it?

-- Rick

Share this post


Link to post
Share on other sites

For the last year, I've been using an Adaptec 2910SA SATA RAID-5 controller which has hardware parity checking done by its on-board processor. This is a fairly high-end and feature-rich PCI card which supports up to 4 drives. I attach 4 Maxtor MaxLine 250GB SATA disks to that. Performance is good (bottleneck is my 32-bit PCI bus slot since I don't have 64-bit PCI on my motherboard) and reliability has been impeccable. It's no fun losing 750GB of data even if you did have a full backup somewhere else. Restoring takes ages, so I'd recommend against buying cheap RAID controllers. Hunt eBay for bargains if you want to spend less.

I decided against motherboard's built-in RAID mechanism because I wanted RAID-5 and I upgrade motherboards quite frequently and a PCI card can be easily transferred from one motherboard to my next.

Share this post


Link to post
Share on other sites
Apple introduced a whole slew of new products today, and dropped prices on a bunch more. Now they're touting their incredibly affordable RAID system:

"Finally, Apple revamped its Xserve RAID rack-mounted storage system. The new Xserve RAID systems come in three models. The first features four 250GB modules and sells for $5,999. "

Makes 3Ware and LSI Logic look absolutely cheap, doesn't it?

Yes it does. Then again not even comparing Apple's offerings... similar products from Iomega or the SANs that Dell sells are still in the expensive catagory for me in my opinion (and what I had originally budgeted for)

Its been a year since I had the Promise S150 SX4 up and running and its been running 24/7 for roughtly 300+ days. No downtime, no driver issues (as I have said in previous posts I have migrated OS a few times) and no problems whatsoever with my drives.... so I must have been "lucky" since there are still many people I met/talked to who regard my card (and my choice) as absolute crap and throws me lines like "Buy a 3Ware"... yet... they have no prior experience with any of the aformentioned brands (not even the simple RAID 0 or 1 built onto motherboards).

Now that my 320GB RAID 5 Array is close to full, I'll be adding another 160GB drive to it to boost it up to 480GB to last me another year before thinking of upgrading again. I'll let you guys know how the "Online Capacity Expansion" feature works once I did that (and if I remember this post still exists).

Share this post


Link to post
Share on other sites
Now that my 320GB RAID 5 Array is close to full, I'll be adding another 160GB drive to it to boost it up to 480GB to last me another year before thinking of upgrading again. I'll let you guys know how the "Online Capacity Expansion" feature works once I did that (and if I remember this post still exists).

193425[/snapback]

yes, please

although I'm looking at the LSI controller myself

Share this post


Link to post
Share on other sites
Now that my 320GB RAID 5 Array is close to full, I'll be adding another 160GB drive to it to boost it up to 480GB to last me another year before thinking of upgrading again. I'll let you guys know how the "Online Capacity Expansion" feature works once I did that (and if I remember this post still exists).

I am contemplating purchasing the sx4, as I want my budget to go mostly to capacity, not necessarily speed. I have posted my question on the [H] but have not been overly impressed with the response. Here it goes:

Can the capacities of the actual drives of a raid5 array be increased? For example...Let's say I build the array with 4 250GB drives for a total of .75TB (man, it's just cooler to use TB instead of GB). Can I swap out each drive with a 400GB drive in the future? I know that as you add each drive, only 250GB will be available...but once all 4 are added, will the total capacity then become 1.2TB? The best answer I got to my question was...no. But no isn't a good enough answer. Can this be done ever, possibly with a different card? Oh, and has anyone else verified that BS about XP recognizing an expanded array as and additional partition?

Share this post


Link to post
Share on other sites

re: joecool234

Technically, yes what you said is what you would do, and that is what the tech told me when I originally purchased my Promise card. You pull out ONE old drive from the array, add the new one in, let it finish rebuild, then repeat this for the remaining 3 drives, and supposedly you are able to use PAM (Promise Array Manager) in Windows (or maybe even inside their BIOS) and use the Online Capacity Expansion feature to "fill" out your array with the rest of the empty space.

I guess you will have to try it out to verify it for sure, or you can try contact Promise (their tech support dept.) and ask them the same question you did here.

Share this post


Link to post
Share on other sites

so does the capacity expansion work on the Promise?

Also, should i rather get the Promise SX4 or the Highpoint 1820A. Both of them 'claim' to have on board parity calculation, but the price point of the HPT adapter is nicer 8 ports for just a couple of extra bucks.

i do not care about Linux drivers, so that is not an issue with me.

Share this post


Link to post
Share on other sites

All I can say is don't go for the Highpoint 1640 card, reasons given here: http://forums.storagereview.net/index.php?showtopic=18424

I'm going to be replacing it with a 3ware card, but if you're interested you can find some reviews on other items here:

http://www.gamepc.com/labs/view_content.as...lcompare&page=4

http://www.gamepc.com/labs/view_content.asp?id=r52005&page=1

http://www.xbitlabs.com/articles/storage/d...se-s150sx4.html

Share this post


Link to post
Share on other sites
All I can say is don't go for the Highpoint 1640 card, reasons given here: http://forums.storagereview.net/index.php?showtopic=18424

I'm going to be replacing it with a 3ware card, but if you're interested you can find some reviews on other items here:

http://www.gamepc.com/labs/view_content.as...lcompare&page=4

http://www.gamepc.com/labs/view_content.asp?id=r52005&page=1

http://www.xbitlabs.com/articles/storage/d...se-s150sx4.html

194516[/snapback]

thanks for the info. I am now sure that I will go for either the SX4, SX4-m the 1820a or the BC4452 :D

Share this post


Link to post
Share on other sites
Now that my 320GB RAID 5 Array is close to full, I'll be adding another 160GB drive to it to boost it up to 480GB to last me another year before thinking of upgrading again. I'll let you guys know how the "Online Capacity Expansion" feature works once I did that (and if I remember this post still exists).

As I have promised a month ago, I am here to report back on my progress now that I am back from my work/vacation for the past 2 months.

Just obtained another HGST 7K250 160GB SATA drive today, installed it to one of my SATA Hot-Swap drive caddy (its an Intel enclosure if you are interested to know), pop it in, wait for the green LED to lit up indicating the drive is powered up and then started the Promise PAM utility. All this while my server and Windows XP (I know, I will be re-installing Win Server 2003 back on it soon) is up and running.

Inside the Promise Array Management tools, I just go straight to the admin panel for the Array and hit the "Conversion/Expansion Wizard" 's START button and let it do the dirty work.

Well its still in progress (its been about 3 hours since I started the expansion) and the status is shown at "Migrating 63%". Its a bit slow but I do have close to 300GB of files on the 320GB array so its close to full capacity at the moment.

The good thing I guess is you can still access all the files from the array... which I guess is normal and to be expected out of a proper RAID card.

CPU usage is shown at a constant 5%-8% while all this is happening and the server is fully functional.

I'll report back in once the expansion finishes. Cheers! :)

Share this post


Link to post
Share on other sites

Well, after going out to get some dinner, the RAID array expansion finished, so I estimated it took about a total of 5 hours or so to "migrate" and expand out my 320GB into a 480GB RAID 5 array, and during this time the server is fully active and you can still read/write to all the data on the array.

I am happy to say that the "Online Capacity Migration" works flawlessly and as expected. Nothing "went wrong" and I now have a fully functioning 480GB 4-disc 160GB SATA RAID 5 array.

The only thing left for me to do is fill up the extra space and then upgrade/migrate to larger sized discs to make a 1TB RAID 5 array... but that will probabally happen next year :)

Share this post


Link to post
Share on other sites
Well, after going out to get some dinner, the RAID array expansion finished, so I estimated it took about a total of 5 hours or so to "migrate" and expand out my 320GB into a 480GB RAID 5 array, and during this time the server is fully active and you can still read/write to all the data on the array.

I am happy to say that the "Online Capacity Migration" works flawlessly and as expected. Nothing "went wrong" and I now have a fully functioning 480GB 4-disc 160GB SATA RAID 5 array.

The only thing left for me to do is fill up the extra space and then upgrade/migrate to larger sized discs to make a 1TB RAID 5 array... but that will probabally happen next year :)

196386[/snapback]

I was wondering is the extra space a new partition? If no, did promise expand the NTFS partition? Are you using dynamic disks?

Share this post


Link to post
Share on other sites
I was wondering is the extra space a new partition? If no, did promise expand the NTFS partition? Are you using dynamic disks?

When I put in the extra 160GB into the Hot-Swap enclosure Windows detected the disc but its not useable or associated with any RAID array.

So, what the "Online Capacity Migration" does (I think its the same for any other RAID cards as well) is to initiate the extra disc you put into the array and make it "avaliable" to whatever OS you are using (which is Windows XP on my server currently). That is if you want to "expand" an existing array... of course you can assign the extra disc to a new array on its own or just leave it as a single disc by itself.

Anyway, after the "Migration Process" within the Promise Array Management Utilities, under "Disc Management" in Windows the extra space will show up as an unassigned empty space within the array set (in my case under "Disc 1, Basic, 458.21GB" drive).

You can either setup a saperate partition for the new empty space, or try and "enlarge" your existing partitions to use up the extra space (in which case you need a disc utility like Norton Partition Magic which I used).

To Windows, the RAID array appears just like a normal single disc drive and you have to setup your own partitions for them. As far as setting/converting them to "dynamic discs" I think its not necessary really.. and I think only needed if you are going to set up a software based Windows RAID array.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now