Proliant buying advice
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@Carnival-Boy said:
You might be interested in reading this regarding SSD life:
http://h20565.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c03312456Basically, HP software monitors the number of writes, and when the limit is reached it puts the drive into a state of predictive failure and you have to replace it.
That's a separate issue. That's not the SSD wearing out, that's HP replacing drives proactively. As long as you are under warranty, that's a free, new drive.
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@scottalanmiller said:
That's a separate issue. That's not the SSD wearing out, that's HP replacing drives proactively. As long as you are under warranty, that's a free, new drive.
I don't think so if this thread is anything to go by:
http://community.spiceworks.com/topic/465098-dell-enterprise-ssd-drives
It's Dell, but I'd guess HP is the same.Incidently, on that thread @Dashrender says he read a drive can write 100GB per day, but on this thread that's inflated to 2TB. I'll bear that in mind if he ever claims to have caught a hundred pound fish
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Well, this article http://arstechnica.com/gadgets/2014/06/consumer-grade-ssds-actually-last-a-hell-of-a-long-time/ indicated they got about 700 TB before drives started to fail in their torture test. My statement of 2 TB is clearly mistaken.
FYI 3 of the drives they were testing where still working, and had written over 1 PB as of the article.
Again these are consumer multi cell drives, not single cell enterprise drives (though the value drives you mentioned might be multi cell drives too).
With your 20 GB DB you'd have to write the entire DB 5 times a day to come close to this type of torture, seems pretty unlikely for an SMB with a DB of that size.
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@Carnival-Boy said:
I don't think so if this thread is anything to go by:
http://community.spiceworks.com/topic/465098-dell-enterprise-ssd-drives
It's Dell, but I'd guess HP is the same.That thread is mostly talking about MLC, not SLC enterprise drives, right? And still the wear is very long.
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@Carnival-Boy said:
Incidently, on that thread @Dashrender says he read a drive can write 100GB per day, but on this thread that's inflated to 2TB. I'll bear that in mind if he ever claims to have caught a hundred pound fish
Thanks - Clearly I haven't read the article in a long time.. 100 GB does seem to coincide with the other article I just posted.
I fixed my other post.
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@Dashrender said:
With your 20 GB DB you'd have to write the entire DB 100 times a day to come close to this type of torture, seems pretty unlikely.
And the more write cache you have on the controller, the less it writes to the disk. And this is why RAID 1 is important with SSDs rather than RAID 5 or RAID 6 which write two or three times for each block instead of just once like RAID 1. Write expansion isn't a concern with longevity on spindle drives but it is on SSDs so the write cache is less for speed and more for longevity in that case.
Having lots of memory reduces writes too.
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So if "Enterprise Value" drives have massive IOPS, massive reliability and massive life expectancy, who buys "Enterprise Mainstream" and "Enterprise Performance" drives, given the massive premiums you're paying for the latter?
Is it possibly a bit of a money-making scam from HP to convince companies to overspend, or am I missing something else?
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@Carnival-Boy said:
So if "Enterprise Value" drives have massive IOPS, massive reliability and massive life expectancy, who buys "Enterprise Mainstream" and "Enterprise Performance" drives, given the massive premiums you're paying for the latter?
We have no idea what those are.
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@Carnival-Boy said:
Is it possibly a bit of a money-making scam from HP to convince companies to overspend, or am I missing something else?
Very possible.
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@scottalanmiller said:
Each port is another full SAS channel with full SAS bandwidth. You want that if you have a place to use it. You don't, so does not matter to you. It is often used when you have an internal array and an external array or a massive internal array that you want to split.
From the specs, the 440ar has 2 internal 4 mini-SAS connectors, whilst the 440 has a single internal 8 mini-SAS connector. So both have 8 connectors, but the ar is split into 2 x 4 for whatever reason (form factor?).
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@Carnival-Boy said:
@scottalanmiller said:
That's a separate issue. That's not the SSD wearing out, that's HP replacing drives proactively. As long as you are under warranty, that's a free, new drive.
I don't think so if this thread is anything to go by:
http://community.spiceworks.com/topic/465098-dell-enterprise-ssd-drives
It's Dell, but I'd guess HP is the same.Confirmed by HP: "Maximum usage limit: This is the maximum amount of data that can be written to the drive. Drives that have reached this limit will not be eligible for warranty coverage.". So whilst normal HDDs will last forever (under the server's warranty), SSDs won't. But this might be irrelevant if no-one ever reaches the maximum usage limit.
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The cheapest SSD drives are SATA. Now with normal HDDs I think I understand the limitations of SATA - 7.2k spindle speed and less reliability (lower MTBF). But I can't find any distinctions between SAS and SATA SDDs other than throughput - 6G SATA versus 12G SAS.
Is throughput likely to be a constraint?
Are there any other differences?
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@Carnival-Boy said:
@Carnival-Boy said:
@scottalanmiller said:
That's a separate issue. That's not the SSD wearing out, that's HP replacing drives proactively. As long as you are under warranty, that's a free, new drive.
I don't think so if this thread is anything to go by:
http://community.spiceworks.com/topic/465098-dell-enterprise-ssd-drives
It's Dell, but I'd guess HP is the same.Confirmed by HP: "Maximum usage limit: This is the maximum amount of data that can be written to the drive. Drives that have reached this limit will not be eligible for warranty coverage.". So whilst normal HDDs will last forever (under the server's warranty), SSDs won't. But this might be irrelevant if no-one ever reaches the maximum usage limit.
Ah, just a sales tactic then. Has nothing to do with the drives wearing out.
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@Carnival-Boy said:
The cheapest SSD drives are SATA. Now with normal HDDs I think I understand the limitations of SATA - 7.2k spindle speed and less reliability (lower MTBF). But I can't find any distinctions between SAS and SATA SDDs other than throughput - 6G SATA versus 12G SAS.
Is throughput likely to be a constraint?
Are there any other differences?
Throughput is constrained but its not bad once you hit 6Gb/s. But the ability to use 12Gb/s is nice for a memory device.
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@scottalanmiller said:
@Carnival-Boy said:
The cheapest SSD drives are SATA. Now with normal HDDs I think I understand the limitations of SATA - 7.2k spindle speed and less reliability (lower MTBF). But I can't find any distinctions between SAS and SATA SDDs other than throughput - 6G SATA versus 12G SAS.
Is throughput likely to be a constraint?
Are there any other differences?
Throughput is constrained but its not bad once you hit 6Gb/s. But the ability to use 12Gb/s is nice for a memory device.
Do you think his situation would even come close to saturating 6 Gb/s?
I suppose it could if he ran a very intensive query... but look at my question more generically. -
An SSD can pump a lot of data very quickly. Remember that we are talking about a memory bus here, not something talking to spindles. So pretty typically an SSD can saturate 6Gb/s. Even a single one.
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Hmmn, I think I may stay old-skool and stick with 16 x 300gb SAS disks.
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Update for those that are interested:
I've compromised in the end and gone with 12 x 300gb storage. This gives slightly less storage than I was hoping for, but means the IOPS is at least as good as we have now. I've also treated myself to a bit extra memory, since it's pretty cheap, so will have 96GB. The ERP system will be given 64GB of this (the max SQL Server standard allows), which will give loads of room to fit the entire database into memory, so there will be very little disk activity anyway.
I'll replace our other two Proliants next year, and may replace them with a single server. So we'll eventually go from 3 hosts down to 2. Although I'm not convinced that two hosts is better than three since disks are the most expensive part and you need more storage with a two host solution (for redundancy).
Quick question - since our ESXi licence only supports 3 hosts, and we have 3 hosts, how easy is it to replace one of the hosts? Will I able to add the new host prior to removing the old host (which would mean temporarily having 4 hosts)?
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@Carnival-Boy said:
Update for those that are interested:
I've compromised in the end and gone with 12 x 300gb storage. This gives slightly less storage than I was hoping for, but means the IOPS is at least as good as we have now. I've also treated myself to a bit extra memory, since it's pretty cheap, so will have 96GB. The ERP system will be given 64GB of this (the max SQL Server standard allows), which will give loads of room to fit the entire database into memory, so there will be very little disk activity anyway.
I'll replace our other two Proliants next year, and may replace them with a single server. So we'll eventually go from 3 hosts down to 2. Although I'm not convinced that two hosts is better than three since disks are the most expensive part and you need more storage with a two host solution (for redundancy).
Quick question - since our ESXi licence only supports 3 hosts, and we have 3 hosts, how easy is it to replace one of the hosts? Will I able to add the new host prior to removing the old host (which would mean temporarily having 4 hosts)?
Nice work
What I would do is move the vm's off the host between the other two hosts (providing you have the capacity) , remove the license and then add the new host, license it and move the VM's to the new server.If you don't have the capacity to do that, it gets a bit more complicated.
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@nadnerB said:
If you don't have the capacity to do that, it gets a bit more complicated.
Not really. You forget that you can install a new copy of ESXi and use it unlicensed with full features.
That should be plenty of time to migrate things.
