Greetings,
We will be upgrading an existing 6080 cluster to a 6280 cluster. We also have a 6080 cluster we'll be adding disks to also. Both clusters are 7-mode. We'll probably end up at 8.1 on both clusters. My 2 questions stem from the disks and shelves being proposed for the upgrades (ds2246 with 450g SAS).
1. We currently have DS4243 shelves with 600gig SAS. I know I can't mix these in the same stack because of the 3/6gb connection differences. I have a free port on each SAS adapter in our 6080s. Can I put the 6gb shelves on the same adapter as long as they are on their own stack? I'm guessing it may not be a best practice, but we don't have any slots free in the 6080 for more cards.
2. I found a white paper that states the 10K drive performance can be up to 20% slower than the 15K SAS drives for random reads. That seems like a pretty big performance it. It also says mixing the disks in aggregates is not recommended. Other than the smaller footprint and better density, I'm not seeing an advantage over using 600g SAS in the DS4243 shelves. Are there any advantages other than the faster SAS backend to warrant going to these shelves in our environment?
Thanks,
Jeff
Loads of our configurations are A port to A port for 10 stack, B port to B port for 20 stack, etc (where one is SAS and the other SATA). I see no reason right off why you couldnt have them on the same adapter. As I understand it, the ports are capable of either 3 or 6gb so really it shouldnt matter.
As for the advantages, density, power, and cooling are the big ones that come to mind. Yeah the shelves aren't cheap, but they're capex and cant be depreciated whereas power and cooling are ongoing. What you may pay for upfront could end up being beneficial in the longer term for dollars and cents saved. As for the mixing disks statement, go with that and dont do it..
Just my $0.02..
Feb 27, 2013 07:46:33 PM, jeff.cleverley@avagotech.com wrote: Greetings,
We will be upgrading an existing 6080 cluster to a 6280 cluster. We also have a 6080 cluster we'll be adding disks to also. Both clusters are 7-mode. We'll probably end up at 8.1 on both clusters. My 2 questions stem from the disks and shelves being proposed for the upgrades (ds2246 with 450g SAS).
- We currently have DS4243 shelves with 600gig SAS. I know I can't
mix these in the same stack because of the 3/6gb connection differences. I have a free port on each SAS adapter in our 6080s. Can I put the 6gb shelves on the same adapter as long as they are on their own stack? I'm guessing it may not be a best practice, but we don't have any slots free in the 6080 for more cards.
- I found a white paper that states the 10K drive performance can be
up to 20% slower than the 15K SAS drives for random reads. That seems like a pretty big performance it. It also says mixing the disks in aggregates is not recommended. Other than the smaller footprint and better density, I'm not seeing an advantage over using 600g SAS in the DS4243 shelves. Are there any advantages other than the faster SAS backend to warrant going to these shelves in our environment?
Thanks,
Jeff
Jeff,
1) Mixing the stack types will actually work, but it's not supported due to performance issues. I have a setup like this in my environment, with two 3g and one 6g shelf on a 3g stack. It works okay, questionable throughput at times though.
Having a 6g stack on its own ports on a 3g card should not be an issue. I just put the very same online this week...
2) I don't believe you can get the 15k 3.5" drives from any vendor starting this year. The industry went en masse to the 2.5" form factor for various reasons. The smaller form factor is supposed to make up for the slower spindle speed w/r/t random read latency.
Fred
________________________________ From: Jeff Cleverley jeff.cleverley@avagotech.com To: toasters@teaparty.net Sent: Wednesday, February 27, 2013 8:33 PM Subject: DS2246 shelves and drives questions.
Greetings,
We will be upgrading an existing 6080 cluster to a 6280 cluster. We also have a 6080 cluster we'll be adding disks to also. Both clusters are 7-mode. We'll probably end up at 8.1 on both clusters. My 2 questions stem from the disks and shelves being proposed for the upgrades (ds2246 with 450g SAS).
1. We currently have DS4243 shelves with 600gig SAS. I know I can't mix these in the same stack because of the 3/6gb connection differences. I have a free port on each SAS adapter in our 6080s. Can I put the 6gb shelves on the same adapter as long as they are on their own stack? I'm guessing it may not be a best practice, but we don't have any slots free in the 6080 for more cards.
2. I found a white paper that states the 10K drive performance can be up to 20% slower than the 15K SAS drives for random reads. That seems like a pretty big performance it. It also says mixing the disks in aggregates is not recommended. Other than the smaller footprint and better density, I'm not seeing an advantage over using 600g SAS in the DS4243 shelves. Are there any advantages other than the faster SAS backend to warrant going to these shelves in our environment?
Thanks,
Jeff
Jeff,
in addition to what Fred mentioned,
* the 6GB connection of the 2.5" disks is on average evening out the slower rotational speed, so that you roughly get the same performance as with the 3.5" disks in a DS4243 shelf. * Don't mix 3.5" and 2.5" in the same RG * if you add a 2.5" RG to an existing aggr, try to make it roughly the same capacity as the existing RGs (to spread the load evenly)
Sebastian
On 28.02.2013 14:47, Fred Grieco wrote:
Jeff,
- Mixing the stack types will actually work, but it's not supported
due to performance issues. I have a setup like this in my environment, with two 3g and one 6g shelf on a 3g stack. It works okay, questionable throughput at times though.
Having a 6g stack on its own ports on a 3g card should not be anissue. I just put the very same online this week...
- I don't believe you can get the 15k 3.5" drives from any vendor
starting this year. The industry went en masse to the 2.5" form factor for various reasons. The smaller form factor is supposed to make up for the slower spindle speed w/r/t random read latency.
Fred
*From:* Jeff Cleverley jeff.cleverley@avagotech.com *To:* toasters@teaparty.net *Sent:* Wednesday, February 27, 2013 8:33 PM *Subject:* DS2246 shelves and drives questions.
Greetings,
We will be upgrading an existing 6080 cluster to a 6280 cluster. We also have a 6080 cluster we'll be adding disks to also. Both clusters are 7-mode. We'll probably end up at 8.1 on both clusters. My 2 questions stem from the disks and shelves being proposed for the upgrades (ds2246 with 450g SAS).
- We currently have DS4243 shelves with 600gig SAS. I know I can't
mix these in the same stack because of the 3/6gb connection differences. I have a free port on each SAS adapter in our 6080s. Can I put the 6gb shelves on the same adapter as long as they are on their own stack? I'm guessing it may not be a best practice, but we don't have any slots free in the 6080 for more cards.
- I found a white paper that states the 10K drive performance can be
up to 20% slower than the 15K SAS drives for random reads. That seems like a pretty big performance it. It also says mixing the disks in aggregates is not recommended. Other than the smaller footprint and better density, I'm not seeing an advantage over using 600g SAS in the DS4243 shelves. Are there any advantages other than the faster SAS backend to warrant going to these shelves in our environment?
Thanks,
Jeff
-- Jeff Cleverley Unix Systems Administrator 4380 Ziegler Road Fort Collins, Colorado 80525 970-288-4611 _______________________________________________ Toasters mailing list Toasters@teaparty.net mailto:Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
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Everyone,
Thanks for the replies. Since this is a short term fix for the next few months I'm going to look into getting some 600g ds4243s. These will match our current "fast" drives and will give us more flexibility where we can use them. When we do the next purchase of 100+TB, we'll have enough to be useful as a group and probably go with the 2.5" profile drives.
Jeff
On Thu, Feb 28, 2013 at 7:36 AM, Sebastian Goetze spgoetze@gmail.com wrote:
Jeff,
in addition to what Fred mentioned,
the 6GB connection of the 2.5" disks is on average evening out the slower rotational speed, so that you roughly get the same performance as with the 3.5" disks in a DS4243 shelf. Don't mix 3.5" and 2.5" in the same RG if you add a 2.5" RG to an existing aggr, try to make it roughly the same capacity as the existing RGs (to spread the load evenly)
Sebastian
On 28.02.2013 14:47, Fred Grieco wrote:
Jeff,
- Mixing the stack types will actually work, but it's not supported due to
performance issues. I have a setup like this in my environment, with two 3g and one 6g shelf on a 3g stack. It works okay, questionable throughput at times though.
Having a 6g stack on its own ports on a 3g card should not be an issue.I just put the very same online this week...
- I don't believe you can get the 15k 3.5" drives from any vendor starting
this year. The industry went en masse to the 2.5" form factor for various reasons. The smaller form factor is supposed to make up for the slower spindle speed w/r/t random read latency.
Fred
From: Jeff Cleverley jeff.cleverley@avagotech.com To: toasters@teaparty.net Sent: Wednesday, February 27, 2013 8:33 PM Subject: DS2246 shelves and drives questions.
Greetings,
We will be upgrading an existing 6080 cluster to a 6280 cluster. We also have a 6080 cluster we'll be adding disks to also. Both clusters are 7-mode. We'll probably end up at 8.1 on both clusters. My 2 questions stem from the disks and shelves being proposed for the upgrades (ds2246 with 450g SAS).
- We currently have DS4243 shelves with 600gig SAS. I know I can't
mix these in the same stack because of the 3/6gb connection differences. I have a free port on each SAS adapter in our 6080s. Can I put the 6gb shelves on the same adapter as long as they are on their own stack? I'm guessing it may not be a best practice, but we don't have any slots free in the 6080 for more cards.
- I found a white paper that states the 10K drive performance can be
up to 20% slower than the 15K SAS drives for random reads. That seems like a pretty big performance it. It also says mixing the disks in aggregates is not recommended. Other than the smaller footprint and better density, I'm not seeing an advantage over using 600g SAS in the DS4243 shelves. Are there any advantages other than the faster SAS backend to warrant going to these shelves in our environment?
Thanks,
Jeff
-- Jeff Cleverley Unix Systems Administrator 4380 Ziegler Road Fort Collins, Colorado 80525 970-288-4611 _______________________________________________ Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
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Fred Grieco -
Jeff Cleverley -
Mike B. -
Sebastian Goetze