how does volume available space relate to disks capacity?

S

SMnasMAN

Contributor
Joined
Dec 2, 2018
Messages
177
(im still at a testing my build / play w freenas stage)

Im aware of the zfs slop space , but my calculations for this 12x 3tb RDz2 pool should be ~ 27.26 TB usuable. (see image, view vols shows 24.0 TB) - what am i missing here? (and why does available on the first line show 32.5 tb?)

my rough calc:
12x 3tb = 36tb
- 2x 3tb disks (parity for rdz2) = 30TB
- 2.5% Slop Space = ~29.25 TB
- formatting/filesys ( 29.25 tb * 0.9323) = ~ 27.26 TB (usable)

(even if i apply the formatting/file sys loss at raw 36tb:
36 *0.9323 = 33.56tb
* 0.775 (20% parity, 2.5% slop) = 26.01tb usable

so where am i off here?

I dont think this should matter: but i used the manual button on Volume manager tool as im using 9x 4TB disks and 3x 3tb disks = 12x disks (each at 3tb).

all disks were quick wiped in FN gui, and this is the only pool they are a part of.

is this maybe it? the bytes to TB conversion? (25.75 Tbytes is closer to my #s):
Code:
# df -h

/mnt/hdd12xRDz2       24T    201K     24T     0%

# df

/mnt/hdd12xRDz2       25750731511     201 25750731310


thanks!

12xdiskCapture.JPG
 
DrKK

DrKK

FreeNAS Generalissimo
Joined
Oct 15, 2013
Messages
3,630
I didn't run your math yet, but you *do* understand the difference between TB and TiB?
 
danb35

danb35

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Aug 16, 2011
Messages
15,504
TB vs. TiB is at least part of the problem. Disks are sold in TB (10^12 bytes), but most OSs measure their capacity in TiB (2^40 bytes). 1 TiB ~= 0.91 TB. So, 12 x 3 TB = 36 TB = 32.75 TiB. That accounts for the first line. As to the second, let's confirm the pool layout. What's the output of zpool status?
 
S

SMnasMAN

Contributor
Joined
Dec 2, 2018
Messages
177
hi,
i am aware of the tb vs TiB difference - that is the point of my line with 36 *0.9323 = 33.56tb (i thought it was 1TiB ~= 0.9323TB) , ie you buy a 1tb disk from store, put it in your windows machine, format it NTFS, your left with ~923tb usable.

here is the otuput of zpool status

thanks for help / replies!

EDIT- UPDATED WITH CORRECT POOL INFO

Code:
 

root@freenas:~ # zpool status
  pool: hdd12xRDz2
 state: ONLINE
  scan: none requested
config:

        NAME                                            STATE     READ WRITE CKSUM
        hdd12xRDz2                                      ONLINE       0     0     0
          raidz2-0                                      ONLINE       0     0     0
            gptid/7b8c582e-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/7c58f573-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/7dec0e35-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/7f789eeb-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/8199cb99-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/83ba2e28-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/86068d79-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/88227a2e-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/8a5a433a-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/8c0f43ec-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/8d919d99-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0
            gptid/8ef19bcf-0c92-11e9-96d6-00259084f1c8  ONLINE       0     0     0

errors: No known data errors


EDIT: here is the output of , glabel status , geom disk list , gpart status - tks

Code:
root@freenas:~ # gpart status
  Name  Status  Components
da12p1      OK  da12
da12p2      OK  da12
 da5p1      OK  da5
 da5p2      OK  da5
ada0p1      OK  ada0
ada0p2      OK  ada0
ada3p1      OK  ada3
ada3p2      OK  ada3
 da2p1      OK  da2
 da2p2      OK  da2
 da3p1      OK  da3
 da3p2      OK  da3
 da4p1      OK  da4
 da4p2      OK  da4
 da9p1      OK  da9
 da9p2      OK  da9
da10p1      OK  da10
da10p2      OK  da10
da11p1      OK  da11
da11p2      OK  da11
da16p1      OK  da16
da16p2      OK  da16
ada1p1      OK  ada1
ada1p2      OK  ada1
 da0p1      OK  da0
 da0p2      OK  da0
 da1p1      OK  da1
 da1p2      OK  da1
root@freenas:~ # glabel status
                                      Name  Status  Components
gptid/be4d6745-fd87-11e8-aab7-00259084f1c8     N/A  da12p1
gptid/90f16b5e-0a4f-11e9-96d6-00259084f1c8     N/A  da5p2
gptid/7b8c582e-0c92-11e9-96d6-00259084f1c8     N/A  ada0p2
gptid/7c58f573-0c92-11e9-96d6-00259084f1c8     N/A  ada3p2
gptid/7dec0e35-0c92-11e9-96d6-00259084f1c8     N/A  da2p2
gptid/7f789eeb-0c92-11e9-96d6-00259084f1c8     N/A  da3p2
gptid/8199cb99-0c92-11e9-96d6-00259084f1c8     N/A  da4p2
gptid/83ba2e28-0c92-11e9-96d6-00259084f1c8     N/A  da9p2
gptid/86068d79-0c92-11e9-96d6-00259084f1c8     N/A  da10p2
gptid/88227a2e-0c92-11e9-96d6-00259084f1c8     N/A  da11p2
gptid/8a5a433a-0c92-11e9-96d6-00259084f1c8     N/A  da16p2
gptid/8c0f43ec-0c92-11e9-96d6-00259084f1c8     N/A  ada1p2
gptid/8d919d99-0c92-11e9-96d6-00259084f1c8     N/A  da0p2
gptid/8ef19bcf-0c92-11e9-96d6-00259084f1c8     N/A  da1p2
gptid/7c4163c2-0c92-11e9-96d6-00259084f1c8     N/A  ada3p1
gptid/7b7be8d8-0c92-11e9-96d6-00259084f1c8     N/A  ada0p1



root@freenas:~ # geom disk list
Geom name: da0
Providers:
1. Name: da0
   Mediasize: 3000592982016 (2.7T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA Hitachi HUS72403
   lunname: ATA     Hitachi HUS724030ALE641                 P8G7T6JP
   lunid: 5000cca22cc3897b
   ident: P8G7T6JP
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: da1
Providers:
1. Name: da1
   Mediasize: 3000592982016 (2.7T)
   Sectorsize: 512
   Mode: r2w2e5
   descr: HITACHI H7230AS60SUN3.0T
   lunid: 5000cca03e11a47c
   ident: 001232R9PTBK        YVG9PTBK
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: da5
Providers:
1. Name: da5
   Mediasize: 500107862016 (466G)
   Sectorsize: 512
   Mode: r2w2e5
   descr: ATA WDC WD5002AALX-0
   lunname: ATA     WDC WD5002AALX-00J37A0                       WD-WCAYUJ413167
   lunid: 50014ee103cc086a
   ident: WD-WCAYUJ413167
   rotationrate: unknown
   fwsectors: 63
   fwheads: 255

Geom name: da6
Providers:
1. Name: da6
   Mediasize: 3000592982016 (2.7T)
   Sectorsize: 512
   Mode: r0w0e0
   descr: HITACHI H7230AS60SUN3.0T
   lunid: 5000cca03e11a364
   ident: 001232R9PR3K        YVG9PR3K
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: da7
Providers:
1. Name: da7
   Mediasize: 3000592982016 (2.7T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r0w0e0
   descr: ATA Hitachi HUS72403
   lunid: 5000cca22ccbd603
   ident: P8GV151P
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: da8
Providers:
1. Name: da8
   Mediasize: 3000592982016 (2.7T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r0w0e0
   descr: ATA Hitachi HUS72403
   lunid: 5000cca22cceba21
   ident: P8H1D9ZR
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: da9
Providers:
1. Name: da9
   Mediasize: 4000787030016 (3.6T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA Hitachi HUS72404
   lunid: 5000cca249c3402e
   ident: P4G74P6C
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: da10
Providers:
1. Name: da10
   Mediasize: 4000787030016 (3.6T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA Hitachi HUS72404
   lunid: 5000cca22bd40887
   ident: PAHE25RS
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: da11
Providers:
1. Name: da11
   Mediasize: 4000787030016 (3.6T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA Hitachi HUS72404
   lunid: 5000cca24cda23c4
   ident: PCHVHM1B
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: da12
Providers:
1. Name: da12
   Mediasize: 15518924800 (14G)
   Sectorsize: 512
   Mode: r1w1e2
   descr: ADATA USB Flash Drive
   lunname: USB MEMORY BAR
   lunid: 2020030102060804
   ident: 2772718120230008
   rotationrate: unknown
   fwsectors: 63
   fwheads: 255

Geom name: ada1
Providers:
1. Name: ada1
   Mediasize: 3000592982016 (2.7T)
   Sectorsize: 512
   Mode: r2w2e5
   descr: Hitachi HUA723030ALA641
   lunid: 5000cca234c12343
   ident: YVG2HL8A
   rotationrate: 7200
   fwsectors: 63
   fwheads: 16

Geom name: da15
Providers:
1. Name: da15
   Mediasize: 120034123776 (112G)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r0w0e0
   descr: ATA INTEL SSDSC2BW12
   lunname: ATA     INTEL SSDSC2BW120H6                     CVTR528006EW120AGN
   lunid: 55cd2e414c8cef3f
   ident: CVTR528006EW120AGN
   rotationrate: 0
   fwsectors: 63
   fwheads: 255

Geom name: da13
Providers:
1. Name: da13
   Mediasize: 80026361856 (75G)
   Sectorsize: 512
   Mode: r0w0e0
   descr: ATA INTEL SSDSC2BB08
   lunid: 55cd2e404b52636c
   ident: BTWL345400GB080KGN
   rotationrate: 0
   fwsectors: 63
   fwheads: 255

Geom name: da14
Providers:
1. Name: da14
   Mediasize: 80026361856 (75G)
   Sectorsize: 512
   Mode: r0w0e0
   descr: ATA INTEL SSDSC2BB08
   lunid: 55cd2e404b525987
   ident: BTWL345308RZ080KGN
   rotationrate: 0
   fwsectors: 63
   fwheads: 255

Geom name: ada2
Providers:
1. Name: ada2
   Mediasize: 120033041920 (112G)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r0w0e0
   descr: Samsung SSD 850 EVO 120GB
   lunid: 5002538da00ea035
   ident: S21VNSAG117944M
   rotationrate: 0
   fwsectors: 63
   fwheads: 16

Geom name: da2
Providers:
1. Name: da2
   Mediasize: 4000787030016 (3.6T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA HGST HUS724040AL
   lunname: ATA     HGST HUS724040ALE640                          PK1338P4GNB5MB
   lunid: 5000cca249c94165
   ident: PK1338P4GNB5MB
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: da3
Providers:
1. Name: da3
   Mediasize: 4000787030016 (3.6T)
   Sectorsize: 512
   Mode: r2w2e5
   descr: ATA HGST HUS724040AL
   lunname: ATA     HGST HUS724040ALA640                          PN2331PAH4GLYT
   lunid: 5000cca22bd01fd6
   ident: PN2331PAH4GLYT
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: da4
Providers:
1. Name: da4
   Mediasize: 4000787030016 (3.6T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA HGST HUS724040AL
   lunname: ATA     HGST HUS724040ALE640                          PK2338P4HB8UAC
   lunid: 5000cca249d338af
   ident: PK2338P4HB8UAC
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: ada0
Providers:
1. Name: ada0
   Mediasize: 4000787030016 (3.6T)
   Sectorsize: 512
   Mode: r1w1e3
   descr: HGST HUS724040ALA640
   lunid: 5000cca22bd02b1d
   ident: PN2331PAH4KM2T
   rotationrate: 7200
   fwsectors: 63
   fwheads: 16

Geom name: da16
Providers:
1. Name: da16
   Mediasize: 4000787030016 (3.6T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r2w2e5
   descr: ATA HGST HUS724040AL
   lunname: ATA     HGST HUS724040ALE640                          PK1334PCKDLWPX
   lunid: 5000cca24cf001e3
   ident: PK1334PCKDLWPX
   rotationrate: 7200
   fwsectors: 63
   fwheads: 255

Geom name: ada3
Providers:
1. Name: ada3
   Mediasize: 4000787030016 (3.6T)
   Sectorsize: 512
   Stripesize: 4096
   Stripeoffset: 0
   Mode: r1w1e3
   descr: HGST HUS724040ALE640
   lunid: 5000cca24cf1ccf5
   ident: PK1334PCKJK5RS
   rotationrate: 7200
   fwsectors: 63
   fwheads: 16
 
Last edited:
S

SMnasMAN

Contributor
Joined
Dec 2, 2018
Messages
177
Crap, you are right. ive been testing different layouts. I will redo and repost in about an hour (ill edit higher up thread, and reply once done). Sorry about that.

btw, im keeping a clean spreadsheet of all my various results and will post that here as well for others to see. im benching ALOT of different layouts on good HW. tks
 
S

SMnasMAN

Contributor
Joined
Dec 2, 2018
Messages
177
ok, i have updated my message above with the correct pool info (i recreated it, gui does ofcouse still show 24 TiB like before).

thanks
 
DrKK

DrKK

FreeNAS Generalissimo
Joined
Oct 15, 2013
Messages
3,630
Sir:

What's 0.9323? Where does that number come from?

Also, 1TiB ~ 1.1TB, the difference is just about 10%. Which you can see by comparing 2^40 to 1 Trillion. Thus, 1TB ~ 0.91 TiB, going in the reciprocating direction.

Not sure what 0.9323 is.
 
S

SMnasMAN

Contributor
Joined
Dec 2, 2018
Messages
177
i ment 0.931 (ie if you google a 1tb disk's formatted capacity = 931gb). Either-way, we are talking small differences in that part of the math. the bigger question is im not clear on how a raw 36tb diskset (12 x 3tb), goes to 24 TiB usable when using raidz2. (or is this bc of the TB to TiB conversion?)

maybe an easier way of answering this question, (ignoring my info/posts above), with 12x 3tb disks setup in a single raidZ2 , how much usuable space should i expect?

thanks
 
S

SMnasMAN

Contributor
Joined
Dec 2, 2018
Messages
177
ok thanks for the replies, im starting to understand now, im coming from the HW raid world which is clearly a bit different (and im aware, worse integrity) i had been using that same zfs calculator you linked to before but i was looking at the TB vs the TiB.

here are some interesting charts / article (you prob have seen this before tho)
direct link (google drive spreadsheet)
https://docs.google.com/a/delphix.c...jHv6CGVElrPqTA0w_ZY/edit?pli=1#gid=2126998674

chart/ss is from this article:
https://www.delphix.com/blog/delphi...or-how-i-learned-stop-worrying-and-love-raidz

thanks
 
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