Mixing SAS Drives in the same array - Same brand/speed - different generation/cache

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Allan74

Member
May 15, 2019
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I have an array that is made up of 2TB Dell branded Seagate Constellations that simply refuses to die or.... even degrade.
I have the opportunity to grab another handful of Dell branded Constellations for literally nothing, but they are a generation older.
Current drives - Constellation ES.1 (7200RPM, SAS 6G, 64MB Cache)
New/old drives - Constellation ES (7200RPM, SAS 6G, 16MB Cache)

Would you mix these drives within the same array ? an existing array ? (SAS2108 based HW RAID5)
Could it be as easy as setting 'Disk Cache Policy' to DISABLED in MR Storage Manager ?
Am I about to introduce problems to my 'array that refuses to die' ?

The current array is made up of 8 drives and I am looking to expand it to 12.
(still SAS2108 based HW RAID5...perhaps RAID6 with additional drives)

SAS-HDDs.jpg

As always, thanks in advance,
Allan
 

i386

Well-Known Member
Mar 18, 2016
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With hardware raid you should always disable the cache on hdds. (Default behavior on adaptec raid controllers)
Yes you can mix the drives (I have a fileserver with 14 hgst hdds and 2 toshiba hdds in the same array and no problemes, even when the toshibas have less platter with higher storage density)

To be honest I wouldn't use 8 year old, small hdds not even for free.
Have you thought about replacing them with newer, larger hdds or even ssds?
 

Allan74

Member
May 15, 2019
132
13
18
Fortunately everything that I keep hot is also backed up in cold storage, as this is simply part of my Plex Media Server Library, so nothing really mission critical.

I had planned to begin upgrading slowly to SSDs, but I simply can't justify the over $100+ CDN per TB....and still rising. For the same price today, it comes down to a 1TB (low end) SSD vs a 4TB Red+ or Ironwolf, so the choice for me, at this point is pretty clear.

I am planning a complete array replacement for some SATA 3TB Constellations that I have, that although a few years newer than the SAS 2TB Constellations, have suffered a much higher failure rate and are showing their age in comparison.