Koozali.org: home of the SME Server
Legacy Forums => Experienced User Forum => Topic started by: Taivo on September 19, 2002, 11:09:25 PM
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Hi
I'm running an E-Smith server on a 7200rpm Seagate Barracuda ATAIV hard disc. The temperature inside the case is quite hot even with a case fan. So for the data protection I was wondering that maybe using RAID mirroring would be a good idea. I would probably use two 40GB Western Digital 5400rpm or 7200rpm drives but then comes the question. Which IDE RAID controller chip or adapter does E-Smith support? I found the list of SCSI and ethernet adapters that are supported by E-Smith but nothing about IDE RAID controllers.
Also If you could give me some tips about installing E-Smith server on a mirrored RAID system I'd be thankful.
I also posted this message to the general dicussion forum but there was no answer. So I try my luck here.
Greetings,
Taivo
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Search the forums for "highpoint". This is just one of a few that has been discussed before.
For an OS independent solution you could look at Mirroring chassis solutions like the Accusys 7500 system.
Kelvin
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I have two suggestions: MRS sub-raid from Darrell May (a little box that holds and controls two ide drives in mirrored config and does not require any drivers, as it appears to the system to be just one ide hard drive); and 3ware cards from 3ware which do need drivers.
I have a number of perfect-running 3ware ide raid installations still running e-smith 4.1.2, but an attempt to compile their source code into a driver for SME 5.x ended up with problems. The forthcoming SME 5.6 may again use a RH standard release kernel, like 4.1.2 did, and thus 3ware may have drivers that are an exact match for the SME kernel again.
Note that the 3ware solution provides a much faster drive array than the MRS does.
http://myezserver.com/mrs-sb-c98-manual.html
Good Luck,
Tom
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Keep in mind if drive performance isn't an issue you can always use software Raid-1. I have a very large amount of disk I/O and I'm using two IDE 5400RPM drives on a Celeron 300. Raid uses very little CPU.
Hope this helped,
Nathan
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> Raid uses very little CPU.
Only RAID-1 (mirroring).
Software RAID-5 can be fairly CPU intensive, hence the preference for hardware solutions if you need RAID-5 (besides, software RAID-5 is not available out of the box with SME).
Kelvin
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Kelvin wrote:
> Search the forums for "highpoint". This is just one of a few
> that has been discussed before.
Be sure to search Google for Promise/highpoint/linux. I expect you'll find most of the advice is to avoid these so-called "hardware" solutions, and to use linux software RAID-1.
Charlie
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I am currently running 5.1.2 with a highpoint 404 (4 controller raid card) with 4-40gig WD drives, in a 1+ 0 configuration.
I worked with another user on this forum (about 4 months ago) to compile drivers compatible with the e-smith kernel. I can repost a link to the files for a driver disk if you are interested in this controller. I have not upgraded to 5.5 because I did not know how to activate the driver disk in the 5.5 version upgrade. (and 5.1.2 is working great anyway!)
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Thanks a lot for your answers.
As I see the best option should be software RAID? Some ultra-quick speeds aren't really what I'm after here. But by the way about how much will software mirrored system be slower than hardware RAID mirroring? The machine itself is a Pentium II 350Mhz with 256MB RAM. I'd only use RAID mirroring.
As a novice Linux user I must ask you the next logical question: How can I use or enable software RAID mirroring with SME server?
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Tavio, with a new installation, using software RAID is just a matter of selecting the RAID option when installing. Unfortunately, there's no direct upgrade from non-RAID to RAID--you'd need to back up the server, do a fresh RAID install, then restore your data.
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Hi Taivo,
While software RAID-1 is your cheapest option by far, if data security is your main concern instead of performance, then it really does not matter too much (unless the option you choose causes the server to crawl - haven't seen that happen in either hardware or software RAID setup so far).
I did a Google search as Charlie suggested and I'm not convinced. I don't wish to get into the debate of whether the Highpoint / promise cards are not "true" hadware raid controllers (I've also come across comments that there are no such things as true "software" RAID ;-) as well some time back). One of the sites I was reading searching Google was highlighting a problem some were having trying to use an Onboard RAID of some motherboard to achieve RAID 0+1 (striped and mirrored - a setup NOT supported out of the box with SME's software RAID procedure anyway), they did not mention the fact that most motherboards use cut down (or "lite") versions of their controller chips for integrated solutions and these integrated chipsets are usually not directly supported by the chipmakers.
My own experiences with Highpoint 370 Based cards in SME servers have all been positive ever since I compiled the drivers for them (from Highpoint's web site). While most lower end cards don't support hot swapping, higher end cards (like Adaptec's 2400A do). If you use software RAID, you have the situation where you will need to either :-
1. configure each drive on separate channels
or
2. configure the drives in a master/slave setup on a single channel.
If using (1), and assuming you have no additional IDE ports on your system and you have an IDE CD-ROM drive daisy chained to one of the drives, you will slow down the drive that is connected with the cd-rom and thus your RAID as well, If using (2), If the master drive fails, depending on the nature of the failure, you will sometimes (very often) find that you have no access to the slave IDE drive either until you remove the dead drive and either replace the dead drive or reconfigure the slave as master (a major disadvantage of IDE as opposed SCSI).
One additional benefit of using a hardware RAID card is you can use them on older motherboards which may not be able to take advantage of ATA66/100/133 drives. The onboard controller of these cards will (depending on version of card) and you can then have better performance as well as protection of mirrored drives over what you can get with just software raid (no matter how efficient your Linux drivers are !).
In any case, a UPS and a tape backup system is probably more useful than both software and hardware raid. If your server shuts down badly (power outage, etc.) there is a GREAT possibility of filesystem corruption, some of which are NOT fixable by fsck, and it won't matter if your drives are mirrored or not, they BOTH get corrupted (been there, done that more often than I care - here to waiting for SME 5.6 to be released). If your drive dies, replace it and restore from backup. True, there will be down time, but if you can afford it all, have it all, UPS, tape and RAID ! :)
Kelvin
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Kelvin,
Your final few comments are what I have been thinking . . .
I still havent got a working software RIAD installation.
I have 2 SG Baraccuda IDE 7k2's and a Pioneer Slot CD.
The HD drives are Masters on each channel and the CD is Slave
on Secondary.
SME Install crawls along and invariabley bombs out with a complaint about hardware or media failure at around 15%
I am now wishing I had just put the £50 towards a tape backup drive and forgotten about trying out software RAID altho it seemed like a good idea.
Does anyone have any views on Seagate IDE Travan drives. DAT seems pretty expensive at £300+ whilst Travan is about £150 here in UK.
BTW My data is backed up to CD anyway - just want an automated system I can install / rely on for customers.
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Hi Graham,
Search the forums for Travan and you will see posts from me (and you will see that I am a great fan of Travans - NOT !).
My advice, stay away from Travans. DATs may be more expensive drives but their media is cheaper and by my experience - far more reliable than Travans.
Kelvin
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Thanks Kelvin,
Are there any other alternative backup devices that work with SME ?
How about the OnStream products ?
Is DAT the only way to go ?
Graham
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Hi Graham,
Last I heard, OnStream's gone bankcrupt. No further news since.
I now use Sony AIT drives instead. The AIT 1A drive prices are close to those of DATs and are also available in both IDE and SCSI. Media is pricey though but better capacity.
If you are going down this direction, forget about flexbackup and use another backup software. Shad Lord's Arkeia contrib for the SME server is one choice - free for a single linux server. Others (commercial) are also available like Tapeware.
Kelvin
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Thanks Kelvin
Although I am slightly worried now - is Flexbackup that bad ?
We had some power cuts round here recently and I am starting to get twitchy
about valid backups etc.
Thanks
Graham
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On a similar subject, how about recovering from RAID-1 (mirroring) problems. Let's say a drive goes bad, and has to be removed from the mirror, leaving just one drive. Has anyone looked at how to restore that RAID-1 once a new drive has been obtained? The data is still there on the surviving drive, but I would rather not do a new install and then use Flexbackup to restore the system. Is there some routine that tells SME to remirror the drive from the good drive?
Recovery is always more interesting and critical to me than backups.
Graham wrote:
>
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> Thanks Kelvin
>
> Although I am slightly worried now - is Flexbackup that bad ?
>
> We had some power cuts round here recently and I am starting
> to get twitchy
> about valid backups etc.
>
> Thanks
>
> Graham
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http://lordsfam.net/downloads/other/raidmonitor/raid-recovery-howto.html
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And as mentioned earlier and in other posts, if you value your data enough or if you are working with other people's data (ie. clients and customers), go hardware RAID with hotswap, etc.
Your customers will think you are a legend if a drive fails and all it takes to recover is to turn a key, remove a tray, swap drives, put back the tray and turn the key. All while the server continues to operate ! ZERO downtime. The hardware RAID automatically rebuilds.
Eg. The Accusys subsystems I sell :-
http://www.quasarsoft.com.au/hardware/index.php?topic=storage
Cheers,
Kelvin
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Kelvin wrote:
> My advice, stay away from Travans. DATs may be more expensive
> drives but their media is cheaper and by my experience - far
> more reliable than Travans.
I agree 100%.
As to Graham's speed problem, I suspect it is the known Intel 845 chipset kernel compatibility issue. He can try tweaking BIOS settings, or (my recommendation) try 6.0beta3.
Charlie