Configuring swap devices on SCALE?

[Mathew]

I've imported a number of pools from my FreeNAS Core after committing a fresh install of SCALE and I've noticed that only a handful of swap md devices were created from the pools of devices with swap allocated on them.

root@nas[~]# swapon -s
Filename Type Size Used Priority
/dev/dm-0 partition 2097148 1000476 -2
/dev/dm-1 partition 2097148 542532 -3
/dev/dm-2 partition 2097148 262020 -4
/dev/dm-3 partition 2097148 77540 -5
/dev/dm-4 partition 2097148 2424 -6

Looking into those, I see:

root@nas[~]# for i in {3..7}; do mdadm /dev/md12$i; done
/dev/md123: 2.00GiB raid1 3 devices, 0 spares. Use mdadm --detail for more detail.
/dev/md124: 2.00GiB raid1 3 devices, 0 spares. Use mdadm --detail for more detail.
/dev/md125: 2.00GiB raid1 3 devices, 0 spares. Use mdadm --detail for more detail.
/dev/md126: 2.00GiB raid1 2 devices, 0 spares. Use mdadm --detail for more detail.
/dev/md127: 2.00GiB raid1 2 devices, 0 spares. Use mdadm --detail for more detail.

..but the system has the following:

root@nas[~]# sfdisk -l /dev/sd* | grep swap
/dev/sda1 128 4194431 4194304 2G FreeBSD swap
/dev/sdaa1 128 4194431 4194304 2G FreeBSD swap
/dev/sdab1 128 4194431 4194304 2G FreeBSD swap
/dev/sdb1 128 4194431 4194304 2G FreeBSD swap
/dev/sdc1 128 4194431 4194304 2G FreeBSD swap
/dev/sdd1 128 4194431 4194304 2G FreeBSD swap
/dev/sde1 128 4194431 4194304 2G FreeBSD swap
/dev/sdf1 128 4194431 4194304 2G FreeBSD swap
/dev/sdg1 128 4194431 4194304 2G FreeBSD swap
/dev/sdh1 128 4194431 4194304 2G FreeBSD swap
/dev/sdj1 128 4194431 4194304 2G FreeBSD swap
/dev/sdk1 128 4194431 4194304 2G FreeBSD swap
/dev/sdl1 40 4194343 4194304 2G FreeBSD swap
/dev/sdm1 128 4194431 4194304 2G FreeBSD swap
/dev/sdn1 128 4194431 4194304 2G FreeBSD swap
/dev/sdo1 128 4194431 4194304 2G FreeBSD swap
/dev/sdp1 128 4194431 4194304 2G FreeBSD swap
/dev/sdq1 128 4194431 4194304 2G FreeBSD swap
/dev/sdr1 128 4194431 4194304 2G FreeBSD swap
/dev/sds1 128 4194431 4194304 2G FreeBSD swap
/dev/sdt1 128 4194431 4194304 2G FreeBSD swap
/dev/sdu1 128 4194431 4194304 2G FreeBSD swap
/dev/sdv1 128 4194431 4194304 2G FreeBSD swap
/dev/sdw1 128 4194431 4194304 2G FreeBSD swap
/dev/sdx1 128 4194431 4194304 2G FreeBSD swap
/dev/sdy1 128 4194431 4194304 2G FreeBSD swap
/dev/sdz1 128 4194431 4194304 2G FreeBSD swap

To make it simple, I have 27 available swap partitions but the system appears to only be using 13 of them. My goal, is to be able to pick what of the 13 drives it's using as some of my pools are slower, rotational drives and others are SSDs.

Thank you all.

 

[Mathew]

Here is why I'd like to reallocate these MD devices:

Size	Type	Dev	Swap Dev	Swap Size
240GB	SSD MLC	sda1		2GB
240GB	SSD MLC	sdb1		2GB
240GB	SSD MLC	sdc1		2GB
240GB	SSD MLC	sdd1		2GB
240GB	SSD MLC	sde1		2GB
240GB	SSD MLC	sdf1		2GB
240GB	SSD MLC	sdg1		2GB
240GB	SSD MLC	sdh1		2GB
25GB	SSD SLC	sdi1	NO SWAP
5TB	HDD 7200RPM	sdj1	md125	2GB
5TB	HDD 7200RPM	sdk1	md125	2GB
5TB	HDD 7200RPM	sdl1	md123	2GB
200GB	SSD SLC	sdm1		2GB
200GB	SSD SLC	sdn1	md126	2GB
5TB	HDD 7200RPM	sdo1	md123	2GB
5TB	HDD 7200RPM	sdp1	md123	2GB
5TB	HDD 7200RPM	sdq1		2GB
200GB	SSD SLC	sdr1	md126	2GB
200GB	SSD SLC	sds1		2GB
200GB	SSD SLC	sdt1		2GB
5TB	HDD 7200RPM	sdu1	md125	2GB
5TB	HDD 7200RPM	sdv1	md124	2GB
5TB	HDD 7200RPM	sdw1	md124	2GB
5TB	HDD 7200RPM	sdx1	md124	2GB
10TB	HDD 7200RPM	sdy1		2GB
10TB	HDD 7200RPM	sdz1		2GB
10TB	HDD 7200RPM	sdaa1		2GB
10TB	HDD 7200RPM	sdab1		2GB

 

[jgreco]

Well, I have no idea what the algorithm is here, but clearly sdn1 and adr1 are undesirable while the rest of it looks pretty good. Three way mirroring is advisable for fault tolerance, and HDD is preferable for endurance.

This looks close to optimal except for the failure to create a swap partition on the last three available HDD's.