Incorrect cache size? (Unraid 6.3.3)


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  MKNSSDRE1TB_MK160830100222344 - 1 TB (sdl)         btrfs  624GB (size) 
246GB (used) 
378 GB (free)
 
  Samsung_SSD_840_Series_S19HNSAD628289A - 120 GB (sdk)          
 

OCZ-VECTOR_OCZ-KP7XM481IQSXC36Q - 128 GB (sdi)

 

I'm not understanding how a raid1 btrfs cache of a 1TB, 120GB, and a 128GB SSD would only total 624GB?

 

Am I missing something here or is this just plain wrong? All these ssds were clean and formatted by unraid.

 

Thanks,

Frosty

       
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7 hours ago, Darksurf said:

I'm not understanding how a raid1 btrfs cache of a 1TB, 120GB, and a 128GB SSD would only total 624GB?

RAID1 means all data will have a copy on another physical disk, so the maximum possible total size with those 3 SSD's would be 248GB. Otherwise there would be data that couldn't have a duplicate on the set.

6 hours ago, johnnie.black said:

Know btrfs issue, size is incorrectly reported when using different size devices.

http://carfax.org.uk/btrfs-usage/ will give you the real usable capacity for a given set of disks and RAID level.

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oops apolgies,

21 minutes ago, jonathanm said:

RAID1 means all data will have a copy on another physical disk, so the maximum possible total size with those 3 SSD's would be 248GB. Otherwise there would be data that couldn't have a duplicate on the set.

http://carfax.org.uk/btrfs-usage/ will give you the real usable capacity for a given set of disks and RAID level.

 

OMG, I should have noticed that. I need to set to RAID0. I just plugged the 1TB drive and immediately was confused by the total. The plan was to RAID1 2x1TB but I didn't have the funds to purchase the second one yet so I was planning on changing the raid and leaving the small ones in. Appears I skipped a step and didn't pay attention. So lame and embarrassing., I just missed a lvl 0 problem and I've been doing this for years.

 

 

 

 

Edited by Darksurf
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10 minutes ago, Darksurf said:

OMG, I should have noticed that. I need to set to RAID0. I just plugged the 1TB drive and immediately was confused by the total. The plan was to RAID1 2x1TB but I didn't have the funds to purchase the second one yet so I was planning on changing the raid and leaving the small ones in. Appears I skipped a step and didn't pay attention. So lame and embarrassing., I just missed a lvl 0 problem and I've been doing this for years.

If you actually use the calculator linked, you will find that you really want "single" instead of btrfs raid0:

 

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3 minutes ago, trurl said:

If you actually use the calculator linked, you will find that you actually want "single" instead of btrfs raid0:

 

You're right, I'll just remove the smaller 2 SSDs and leave the RAID1 settings in place for when I get the second 1T SSD. Thanks for the info. Sorry about the confusion. I should know not to jump to conclusions and post in forums after midnight. 

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