Whole disk ZFS or -a4k partition

[Alexandr]

03.07.2013 12:39, Steven Hartland пишет:
> ----- Original Message ----- From: "Alexandr" <shuriku at shurik.kiev.ua>
>
>
>> Hello, community!
>>
>> I have a laptop with 2 disks - mSATA 32Gb SSD and 500Gb HDD. I plan to
>> use SSD as whole disk ZFS pool with root and /usr partitions and 500Gb
>> SATA as ZFS pool for /home and /var. My questions are:
>>
>> 1. Do I need to create a 4k aligned partition on HDD for zfs pool or
>> best to use a whole disk?
>
> As you need a boot partition you will need to 4k align and ensure
> the zpool is created with 4k sectors using gnop hack.
On ssd I have whole disk zpool and boot sector installed manually with dd:

dd if=/boot/zfsboot of=/dev/ada1 count=1
dd if=/boot/zfsboot of=/dev/ada1 skip=1 seek=1024


>> 2. Where the best place for swap - ssd or hdd? SSD is much faster, but
>> with limited write life cycle.
>
> I'd use the ssd for the performance as in general you wont see
> significanlty higher wear leveling than general use unless you're really
> low on RAM and then you will want it as quick as possible anyway.
My laptop has 8Gb DDR3 and core-i5 3210. But when hdd disk io is
intensive, laptop becomes very slow and sometimes totally unusable.
Using ssd as cache or log device for zpool didn't help and I decide to
move system to ssd and leave at hdd only /home and /var partitions. Also
I noticed than system becomes slow when using swap.
>
> If you want ZFS TRIM ensure you use a recent stable/8, stable/9 or head.
Yes, I'm using latest 9.1-STABLE #29 r252340M
>
> Regards
> Steve
>
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