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5612
September 13th, 2019 10:00
Adding new SAS HDDs to Compellent SC2020
I intend to expand my current SC2020 storage with SAS 7K disks.
I have 10 empty slots, so ideally I'd like to use the highest possible capacity per HD.
I have contacted Dell in Brazil and they only have 1TB SAS 7K disks.
I checked my storage and it uses "Dell" 1TB SAS ST1000NX0453 disks (actually Seagate disks).
Having a look at the Seagate datasheet the higher capacity drive of the same family is ST2000NX0433 (SAS 12GB/s 5xx Native just as ST1000NX0453 is).
So I intend to buy the Seagate drives from a reseller (as Dell doesn't sell them).
Does anyone know if this will work? As per storage specs, it seems yes, but I know Dell storages can be finicky...
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Origin3k
4 Operator
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2.3K Posts
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September 16th, 2019 23:00
From Powervault MD3/ME4 and up you can only use Dell branded and certified disks within the array. Its the same with all the other "Major" Vendors. If you dont like this.... buy Supermicro next time.
The SCv2020 is EndOfSale since a couple of month now. Vendors often doesnt certify the latest available disks sizes for the arrays especially when they comes to the end of life and the succesor is already there. Same is true for the SC4020 and the 2.4" 10K SAS drive which is not available.
If you one need a couple of more TB just buy a few Dell (SCv) 1TB drives. If you need much more consider to add a SC300 which is the 3.5" JBOD option for SCv30x0 which also is certified for the old SCv20x0. But depending on the already lifetime of your SCv2020 it doesnt make so much sense.
Again... a non certified disk will not work in your SCv2020.
Regards,
Joerg
DELL-Bob Mi
2 Intern
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230 Posts
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September 14th, 2019 09:00
No, this will not work. When you buy disks from an outside retailer they will not have the firmware installed allowing them to be recognized by the SAN. So when they are added they will not even show up in the system.
Also, since you have 1 TB disks you should add additional 1 TB disks to avoid having uneven Raid extents. If there is a mix of different size of disks installed in the Compellent SAN this can adversely affect the speed that the SAN is capable of. In the event mixed sizes of drives are used in the same tier of storage, performance can be negatively impacted as the smaller drives are filled to capacity and new RAID devices are created with smaller quantities of drives.
Let’s look at an example of how this would affect a Compellent SAN. You currently have a Compellent system that has a single Tier of storage. All of the disks are 7K disks which have an average Input/output operations per second (IOPS) of 70. There is 1 Enclosure of 24 disks so once you add 10 disks there will be 24 active disks. These disks will be made up of 2 different sizes; 14 - 1 TB and 10 - 2 TB. When all of the disks are empty the system has full performance of approximately 1680 IOPS. But once the disks start to fill up, the system begins to lose performance. For example once the 1 TB disks are full this reduces the available IOPS to 700.
Balthar007
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September 16th, 2019 07:00
Thanks a lot for the reply.
If I understood correctly:
1-There is a specific Dell firmware required for any disk purchased. So even if I purchase a 1TB Seagate ST1000NX0453 (same base model), it won't work, as it has to have a Dell firmware. So I'm effectively locked in on Dell as the only disk supplier.
2-The IOPS reduction case is pretty clear in your explanation. But if (1) above is false and a ST2000NX0433 disk would work if the ST1000NX0453 disks didn't exist, I might decide to replace all ST1000 disks instead of trying to expand the storage using them. I actually have 7 SSDs and 7 HDDs delivering different volumes, so I would replace the 7 ST1000 HDDs with ST2000 ones, doubling my current capacity and gaining a lot of slots. It is cheaper to do that than buy 7 extra ST1000 HDDs from Dell...
5X5CX62
1 Rookie
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23 Posts
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October 12th, 2019 21:00
Hmmm can I use SCv360 with SCV2080 then?