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Specking out a new Mac Pro, I could use some advice Raid card / configuration
- Thread starter IFixTheInternet
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Could anyone spare we a simplified version of what the battery back up on a Raid is actually doing?
Also if I have 4 matching 500GB HDs Raid 5 or 6 together and one failed how bad off would I be if I threw in a 320GB or 750Gb drive in to repalced the failed 500GB drive?
Also if I have 4 matching 500GB HDs Raid 5 or 6 together and one failed how bad off would I be if I threw in a 320GB or 750Gb drive in to repalced the failed 500GB drive?
UltraNEO*
macrumors 601
From my understanding, the Battery backup is there to maintain the contents of the write-cache, which could store as much as 256Mb of unwritten data. In the event of a blackout, this battery would keep the content safe and without it (or a suitable UPS) the data would of been lost!!!
For me, I've taken the UPS route. As it'll serve as an anti-surge protector too, offering between 3-5 hours of workable system uptime.. while someone sorts out the electrics. Though others have suggested it's best to have both active.
UltraNEO is correct, it maintains the cache data if power is lost. It's not perfect though, because if the file being written is larger than the cache, you still get a corrupted write.
If you're using the system daily, and a drive failure occurs, you should be OK with RAID 5, as you're there to replace the drive. Keep in mind, if you do replace a drive, it needs to be the same size or larger. A smaller drive won't work, as it just doesn't have the space to make a duplicate. (The Partitions must match exactly).
Yes it does, but not all cards are limited to 256MB. Some have up to 4GB. 😱 😛
Neither is perfect, and ultimately, can't solve absolutely every possiblity even when used together, but to me, a UPS is really a mandatory item, as it solves far more problems than a BBU (battery backup). Ideally, you should combine the two, but it's up to the individual to decide. Usually budget related.
It should be noted, that some companies offer battery backup units, but don't actually recommend it. 😱 Areca falls into this category. ATTO Tech lists a battery backup as an option, but doesn't actually offer it. I've never found one anyway, and Atto doesn't sell them either. (They do sell their other products directly, so I saw this as a hint). 😉
Now there's been some posts back and forth on whether the battery backup presence automatically enables/disables the cache. To be safe, I'd contact the manufacturer to make certain.
I can tell you, that this is not the case with Areca, Atto Tech, or HighPoint. The cache will work without the battery installed.
Hypothetical: I could start with all 4 drives at 500GB giving me about 1.5TB usable (conservative guess).As they fail and I'm sure they will, I could replace with larger drives, which would keep the raid stable but one they have all been replaced with equally larger drives I could initialize the raid and presto RAID is now larger. Kind of growing it over time, so when they have all been replaced the Array will have grown in relation to the data being constantly added to it. Also off setting the cost of buying all the larger drives at once. Any thoughts...?
This is usually how capacity is increased in an existing array. It's easy, and no down time, but the rebuilds may take longer than starting from scratch (you won't have to re-initialize in this case once all the drives are upgraded). 🙂
You can always go larger, just not smaller. 😀
Initialization BTW, erases all the data on the array. 😱 Backups are needed, and in some cases, if the need to upgraded capacity is extremely dire, can allow you to upgrade all the drives at once, initialize, then restore the data from the backup to the new array. Also handy if a major problem occurs, whether changing out for larger drives or not. Backups are notably cheaper than data recovery. 😉
Assuming you do have such a backup, can afford to allow the system to be down, and the $$$ to upgrade all the drives at once. 😉 😛
hayduke
macrumors 65816
If I'm not mistaken Apple's RAID card requires that all drives be of the same capacity. Not sure which card you decided to go with...long-ish thread.
That's with any of them, not just Apple. 😉
JBOD is the exception though. Handy for stringing a bunch of miscellaneous drives into a single large capacity drive. Keeps them from gathering dust anyway. 😛
Longish? Nah... Not yet anyway. 😉 😛
So far I have coming my way a Mac Pro 2.8 dual quad, with 320GB HDD, 2GB RAM, Air port extreme card, 3yr apple care, with my education discount that worked out pretty well. $3060
(4) Hitachi Deskstar P7K500 500GB Hard Drive - 7200, 16MB, SATA-300, OEM $240
(2) OCZ Platinum XTC 4GB Dual Channel PC6400 Memory - DDR2-800MHz, Enhanced Bandwidth, 4096MB (2 x 2048MB) $60
I'm really leaning toward the CalDigit RAID Card for 16 Drives w/ Battery Backup but have not order it yet. Which should be about $500
Assuming everything works the may I want, I would come in under 4K, very nice. I'll have to settle with the 20" samsung LCD I have for now but I'm sure I'll upgrade that in a month or so.
So I am planing on running all the OS updates when I get it and start installing applications. Once the drives arrive and I get a card I'll relocate the OS drive to the optical bay and start moving data onto the array. I'm a bit giddy. I haven't felt like this over a computer since I order my first laptop a few years ago. The last desktop that was truly mine was a gateway and I don't even remember the specs, (I was in 9th grade). So this tower is by far going to be the most powerful computer I have ever worked with. Given my job it woun't be the most costly I've worked with. Netapp shelves run about 10k a piece and we have racks full of them.
(4) Hitachi Deskstar P7K500 500GB Hard Drive - 7200, 16MB, SATA-300, OEM $240
(2) OCZ Platinum XTC 4GB Dual Channel PC6400 Memory - DDR2-800MHz, Enhanced Bandwidth, 4096MB (2 x 2048MB) $60
I'm really leaning toward the CalDigit RAID Card for 16 Drives w/ Battery Backup but have not order it yet. Which should be about $500
Assuming everything works the may I want, I would come in under 4K, very nice. I'll have to settle with the 20" samsung LCD I have for now but I'm sure I'll upgrade that in a month or so.
So I am planing on running all the OS updates when I get it and start installing applications. Once the drives arrive and I get a card I'll relocate the OS drive to the optical bay and start moving data onto the array. I'm a bit giddy. I haven't felt like this over a computer since I order my first laptop a few years ago. The last desktop that was truly mine was a gateway and I don't even remember the specs, (I was in 9th grade). So this tower is by far going to be the most powerful computer I have ever worked with. Given my job it woun't be the most costly I've worked with. Netapp shelves run about 10k a piece and we have racks full of them.
Good to hear you're getting started. 🙂
The Hitachi's may be a problem though. In general, they absolutely refuse to help resolve firmware issues.
IIRC, CalDigit began using Hitachi's, then switched to Seagate's, had even more problems, and switched back to the Hitachi's. Given this, and the dealings I've recently encountered, I wouldn't use them. Period.
Keep in mind, you really should take a look at enterprise units, no matter the brand. Fewer problems, and you're data is safer IMO. Any good drive should work internally connected to the CalDigit.
The memory must be FB-DIMM (Fully Buffered, ECC). Nothing else will work, including the OCZ Platinum memory you ordered. 🙁
Check out OWC, as they have the correct memory, good prices, and are a reliable company to deal with. 🙂
Not to be a doubter but I wet and check through the mac pro specs and you were right. Luckily my order hadn't shipped and they were able to cancel the memory without any problems. And apparently the hard drives 500GB for $60 are on back order and wouldn't arrive for over a month so I canceled those too. I need something a bit sooner than that. So I'm back on the search for memory and hard rives, and I though I was so close.....
Thanks for saving me some aggravation on the RAM, I would have been pissed if if got the wrong sticks installed them and couldn't return them.
Whew... You lucked into avoiding that one. 😉 😛
For a 500GB HDD, you might want to take a look at the WD RE3. It might be worth contacting CalDigit first though, as they've had problems with HDD's working (consumer units). Maybe they've tested these, but I'm not sure, as they've been content to stick to consumer drives. Saves them $$$, as the Hitachi's retailed for ~$67 or so last I looked.
Good luck. 🙂
hayduke
macrumors 65816
FYI I have an older Mac Pro so I'm looking at this:
http://www.transintl.com/store/category.cfm?Category=2649&RequestTimeOut=500
The price is pretty good. I'm also leaning away from upgrading to a RAID card given the trouble and complexity. You can read more about what I'm thinking my set-up will be here:
https://forums.macrumors.com/threads/625435/
That memory would work quite nicely. 🙂
Another good site, BTW. 😉
As for RAID's complexity, the problems usually come down to improper research, particularly with setups made using parts that don't work together.
If you get the correct gear, you'll be fine. The research does take time though, and is a little more difficult in a Mac, as not as many options are available.
Hardware can offer some important benifits that a software RAID can't touch. Cache, backups of the Partion Tables, and they don't rely on the CPU for parity calculations to name a few.
Given the drives you wish to use, and the configuration, RAID may not help. Reconfigure them, and it might.
Look at it this way. You have a fast computer, but the drive throughput is an achiles heel. RAID can make a drastic improvement, and addresses this issue quite nicely. 🙂
BTW, why use a 750GB drive to backup a single 300GB?
lostngone
macrumors 65816
I would disagree with nanofrrog, putting the boot partition on a separate non-raided drive is a bad idea. You lose all the uptime benefits RAID can give you if that boot drive fails. You can still keep the boot volume on a different partition within the same array. I don't really see array initialization time as a big problem because I don't reboot HA systems that often(but you may).
I will agree that no matter what RAID configuration you pick a good off-site backup plan will almost always save you in the end.
Still waiting on the tower to arrive.....
My patience is wearing thin....
I think I got the RAM right this time
8.0GB Mac Pro Memory Matched Pair (2GB x 4) PC6400 DDR2 ECC 800MHz 240 Pin FB-DIMM Modules From OWC (Thanks again nanofrog for spotting that)
My patience is wearing thin....
I think I got the RAM right this time
8.0GB Mac Pro Memory Matched Pair (2GB x 4) PC6400 DDR2 ECC 800MHz 240 Pin FB-DIMM Modules From OWC (Thanks again nanofrog for spotting that)
Sorry, I missed this one. 😱
The idea for keeping the OS on a separate drive is simple. If it fails, you replace the drive, and reload the OS, hopefully from a previous and accurate clone. Simple, and you're done with it. 😉
If it's on the array, it lowers the available space. If a separate drive on the RAID controller, it takes longer to boot (initialization), and it consumes a port that can be used to expand the data array.
And, if the array should fail, the OS is unaffected, lowering the amount of time and effort needed to get the system operational again.
As I understand it, this method is fairly common. At least in what I've seen.
The downside, is it does require a separate drive, and the space to physically install it. More $$$. Not really an issue in a server tower, as they have the space, so mounting hardware is cheap or not even needed. Reliability is paramount, so the cost of a drive is an after thought. Especially when compared to data recovery services. 😉
The situation is slightly different in a Mac Pro though. The mounting hardware is about or more expensive than a drive (depends on size of course). The total cost would have to be evaluated on a case by case basis, but if the data is critical, it's justified IMO. If the IT support is being paid for, that is another reason to do it, as it isn't cheap if contracted on a per incident basis. Though I presume not an issue in IFixtheInternet's case. 😛
Good planning helps, as well as good DIY skills, but there's no absolutes. Particularly with cabling, in my experience. 😱
I've ordered the wrong lengths on few occasions, so now I just buy a larger range of cable lengths. Cables are cheap enough. 😛
Given your previous posts, I presume your machine doesn't use the 800MHz variant, so that memory will work. 😀
Sorry about that.
At the time I posted, I was thinking of the 667MHz variant for some strange reason. 😱 Maybe that will teach me not to post while eating on my lunch break. 😱 😛
But yes, it's the correct type, FB-DIMM, so it will work. 😀
Indeed... Lunch break posting can be hazardous, but typically its your keyboard that suffers.... I think I will get it tomorrow midday. I am on the FedEx tracking site like white on rice. ;-)
I think I found the HDs I want.
http://www.seagate.com/www/en-us/products/servers/barracuda_es/barracuda_es/
They should be able to handle the abuse I will put them through.
I think I found the HDs I want.
http://www.seagate.com/www/en-us/products/servers/barracuda_es/barracuda_es/
They should be able to handle the abuse I will put them through.
The Barracuda ES.2's are good, as well as the WD RE2 series. (I'm interested in the newer RE3's, but haven't used one yet). 😉
Seagate's consumer drives are another story, though. Especially if you need firmware. 😱
Another good reason to skip the consumer drives. 😛
So I am sitting at home doing absolutely nothing.
I should be at work but I am not.
I could be outside enjoying the beautiful weather, I am not.
I am waiting on FedEx.
But it gets better.
I am sitting here patiently waiting and I here a knock at the door. Faintly as it sounded I rush upstairs and open the door with a smile on my face. There is the FedEx man. But he does not have a box large enough to be my Mac Pro... He asks me if I could sign for my neighbors package. I look at him in utter disbelief thinking maybe its still in the truck... I asked him and he had no clue. Apparently my package is on another truck and won't be here till later. I signed for the neighbors package and shut the door. I can't describe the sad expression on my face, but it must have been pretty like a child be told they could not go to Disney World...
So I am still sitting here with absolutely nothing to do...
You might ask why wait? Go out and enjoy the day, or at least go to work...
Every time, FedEx, or UPS for that matter, comes to my place. They miss me and I end up driving 30 minutes there (in good traffic) to one of the worst sides of downtown LA. Then standing at the FedEx warehouse for 20 minutes. Though that is not the worst of it. I would than have to carry the 60LBS machine up 4 stories, and frankly after paying this much money, I'm in no rush to walk up the stairs myself.....
I should be at work but I am not.
I could be outside enjoying the beautiful weather, I am not.
I am waiting on FedEx.
But it gets better.
I am sitting here patiently waiting and I here a knock at the door. Faintly as it sounded I rush upstairs and open the door with a smile on my face. There is the FedEx man. But he does not have a box large enough to be my Mac Pro... He asks me if I could sign for my neighbors package. I look at him in utter disbelief thinking maybe its still in the truck... I asked him and he had no clue. Apparently my package is on another truck and won't be here till later. I signed for the neighbors package and shut the door. I can't describe the sad expression on my face, but it must have been pretty like a child be told they could not go to Disney World...
So I am still sitting here with absolutely nothing to do...
You might ask why wait? Go out and enjoy the day, or at least go to work...
Every time, FedEx, or UPS for that matter, comes to my place. They miss me and I end up driving 30 minutes there (in good traffic) to one of the worst sides of downtown LA. Then standing at the FedEx warehouse for 20 minutes. Though that is not the worst of it. I would than have to carry the 60LBS machine up 4 stories, and frankly after paying this much money, I'm in no rush to walk up the stairs myself.....
I'd sit there and wait too. 😀 😛
Though I try to get things sent to work when possible. 😉