Would it be too risky to connect 2 expanders RES2SV240 to the LSi 9264-8i controller? the expander would have 5 ports left and I plan on connecting 2TB SATA HDD x20 to each expander, and setup RAID 6 on both of them and that should yield approximately 36TB per expander, would the RAID card get fully saturated with total of 40 drives connected? what can I expect from read/write performance on setup like that?
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LSi 9265-8i with 2 expanders RES2SV240?
- Thread starter ben805
- Start date
Well, what kind of workload are you going to be putting on the array(s). is this a home server with a few users or a business server with many? What are you using the box for? Is it just a file server? What kind of data will predominantly be on the box (Video, Audio, Email, Office Files etc). Lots of small files or lots of large ones?
As to speeds.. Lets start with theoretical bandwidth (though it doesn't get this good in real life). The card itself is a x8 PCIe2 board (theoretical bandwidth 4,000MB/s.) Even with 36 average SATA drives (~100MB/s) (40-4 parity at your specs) running full throttle and scaling 100% linear (they wont) you still won't run out of theoretical bandwidth. As to the links between the card and the expander, you have 4 6Gb/s lanes per expander, so even if you broke up the 4GB/s the PCIe bus theoretically supports, that gives you 2GB/s for 18 drives (20-2 parity)
Unless you have REALLY good backups and can survive very extended rebuilds, I generally recommend no more than 14 drives per R6 array. That might screw with your numbers or lose additional drives to parity, but it is a good recommendation to follow.
Lastly, of the equipment... What do you have already and what are you planning on purchasing? What enclosure(s) are you looking at? What OS?
In the end, risk is a balance and is often dictated by dollars.. For example, if you are running 2 completely seperate arrays is it riskier to use 1 controller instead of 2? Sure, it introduces 1 point of failure for 2 arrays. Is it "less risky" to use 2 seperate HBA's with 2 seperate epanders? Probably.. Does it cost more, sure? The question is where do you draw the line. What is your backup strategy for the 72TB of data you plan on maintaining?
As to speeds.. Lets start with theoretical bandwidth (though it doesn't get this good in real life). The card itself is a x8 PCIe2 board (theoretical bandwidth 4,000MB/s.) Even with 36 average SATA drives (~100MB/s) (40-4 parity at your specs) running full throttle and scaling 100% linear (they wont) you still won't run out of theoretical bandwidth. As to the links between the card and the expander, you have 4 6Gb/s lanes per expander, so even if you broke up the 4GB/s the PCIe bus theoretically supports, that gives you 2GB/s for 18 drives (20-2 parity)
Unless you have REALLY good backups and can survive very extended rebuilds, I generally recommend no more than 14 drives per R6 array. That might screw with your numbers or lose additional drives to parity, but it is a good recommendation to follow.
Lastly, of the equipment... What do you have already and what are you planning on purchasing? What enclosure(s) are you looking at? What OS?
In the end, risk is a balance and is often dictated by dollars.. For example, if you are running 2 completely seperate arrays is it riskier to use 1 controller instead of 2? Sure, it introduces 1 point of failure for 2 arrays. Is it "less risky" to use 2 seperate HBA's with 2 seperate epanders? Probably.. Does it cost more, sure? The question is where do you draw the line. What is your backup strategy for the 72TB of data you plan on maintaining?
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Well, what kind of workload are you going to be putting on the array(s). is this a home server with a few users or a business server with many? What are you using the box for? Is it just a file server? What kind of data will predominantly be on the box (Video, Audio, Email, Office Files etc). Lots of small files or lots of large ones?
As to speeds.. Lets start with theoretical bandwidth (though it doesn't get this good in real life). The card itself is a x8 PCIe2 board (theoretical bandwidth 4,000MB/s.) Even with 36 average SATA drives (~100MB/s) (40-4 parity at your specs) running full throttle and scaling 100% linear (they wont) you still won't run out of theoretical bandwidth. As to the links between the card and the expander, you have 4 6Gb/s lanes per expander, so even if you broke up the 4GB/s the PCIe bus theoretically supports, that gives you 2GB/s for 18 drives (20-2 parity)
Unless you have REALLY good backups and can survive very extended rebuilds, I generally recommend no more than 14 drives per R6 array. That might screw with your numbers or lose additional drives to parity, but it is a good recommendation to follow.
Lastly, of the equipment... What do you have already and what are you planning on purchasing? What enclosure(s) are you looking at? What OS?
In the end, risk is a balance and is often dictated by dollars.. For example, if you are running 2 completely seperate arrays is it riskier to use 1 controller instead of 2? Sure, it introduces 1 point of failure for 2 arrays. Is it "less risky" to use 2 seperate HBA's with 2 seperate epanders? Probably.. Does it cost more, sure? The question is where do you draw the line. What is your backup strategy for the 72TB of data you plan on maintaining?
I'm running win7 64bit OS on a core i7 with 12GB ram, this is my media center and I also use it for photo and HD video editing. I plan on using the setup solely for home networking only, sharing and streaming blueray files to 3 other workstations around the house. 2x win7 and 1 winxp machines. The storage will be use mainly for storing a huge collection of blueray and dvd movies, and loads of 1080p video files from my HD camcorder and Canon 5DMK2. The smallest file size will be 30MB (from 5DMK2 raw file) and the biggest will be from blueray rips, which can go up to 40~50GB each. They will see zero small files.
I'm going to get a separate full tower case with a standalone PSU, to power 20 drives and the Intel expander card (run off of molex), they will be cooled by 4x 140mm intake fans and 4x 140mm exhaust fans. It will be setup right next to my workstation with a 3ft mini sas cable from the 9265 running out of an open slot into the HDD tower. I know it sounds a bit ghetto but I do not want to deal with high fan noise from a full blown storage shelf, and I do not need hotswap. The second HDD tower will be the backup, the PSU will be hardwire to an on/off switch, it will only be power on for backup purpose, otherwise it will remain power off. If the main HDD tower go down for whatever reason, then the 2nd tower will be power on to take over the duty while I rebuild or fix the main tower.
My goal is to get the most storage space with highest performance and redundancy with the least amount of money. ;-p
I would second... 20 drive RAID 6 x2 isn't a good idea. As you increase the number of drives within a set you're upping the chance of a HDD failure. R6 can handle 2 failures and no more. If you have a third there goes your whole set.
One of the methods when dealing with high density is to chop up your Raid Collections and then pool where needed. This way a pool can have 2, 3, or 4 collections supporting it. Doing it this way means if the stars align you can withstand 4,6, or 8 drive failures. Even if you receive more than 2 failures within a set you're still in much better shape because you'll only lose that portion of the pool.
In terms of cases since you are talking 40 drives you'll have to split up the cases anyway so it's whatever you want.
One of the methods when dealing with high density is to chop up your Raid Collections and then pool where needed. This way a pool can have 2, 3, or 4 collections supporting it. Doing it this way means if the stars align you can withstand 4,6, or 8 drive failures. Even if you receive more than 2 failures within a set you're still in much better shape because you'll only lose that portion of the pool.
In terms of cases since you are talking 40 drives you'll have to split up the cases anyway so it's whatever you want.
I'm running win7 64bit OS on a core i7 with 12GB ram, this is my media center and I also use it for photo and HD video editing. I plan on using the setup solely for home networking only, sharing and streaming blueray files to 3 other workstations around the house. 2x win7 and 1 winxp machines. The storage will be use mainly for storing a huge collection of blueray and dvd movies, and loads of 1080p video files from my HD camcorder and Canon 5DMK2. The smallest file size will be 30MB (from 5DMK2 raw file) and the biggest will be from blueray rips, which can go up to 40~50GB each. They will see zero small files.
I'm going to get a separate full tower case with a standalone PSU, to power 20 drives and the Intel expander card (run off of molex), they will be cooled by 4x 140mm intake fans and 4x 140mm exhaust fans. It will be setup right next to my workstation with a 3ft mini sas cable from the 9265 running out of an open slot into the HDD tower. I know it sounds a bit ghetto but I do not want to deal with high fan noise from a full blown storage shelf, and I do not need hotswap. The second HDD tower will be the backup, the PSU will be hardwire to an on/off switch, it will only be power on for backup purpose, otherwise it will remain power off. If the main HDD tower go down for whatever reason, then the 2nd tower will be power on to take over the duty while I rebuild or fix the main tower.
My goal is to get the most storage space with highest performance and redundancy with the least amount of money. ;-p
One suggestion will be to get yourself some of these one for your main system and one for the extension array. You can use the SFF-8087 internal cables inside the cases and then use a SFF-8088 to SFF-8088 to link the 2 enclosures. It will put less stress on the connectors than with internal cables running out a slot cover between the two. It is available in standard slot cover size for your computer case and in centronics size for most external enclosures.
Now, as to the drives... Do you own them already or are you going to purchase them... If you don't have them already, here is my suggestion.. If you were to stick to the suggested 10-12 drives per R6 array, 20 2TB drives (10 per array) will yield you 32TB (after parity loss). If you use 3TB drives instead, just 12 drives yields you 30TB (after parity loss) in a single array. 8 drives fewer (well, 16 drives fewer in the two enclosures vs 2TB). A lot less heat, a lot less power, less noise and more choices on your enclosures (A great case like the Fractal XL I have with a Lian-Li mount give you 14 3.5" and 2 2.5" mounts)..
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