Re: [zfs-discuss] Dedicated metadata devices

2012-08-25 Thread Jim Klimov
> No they're not, here's l2arc_buf_hdr_t a per-buffer structure > held for > buffers which were moved to l2arc: > > typedef struct l2arc_buf_hdr { > l2arc_dev_t *b_dev; > uint64_t b_daddr; > } l2arc_buf_hdr_t; > > That's about 16-bytes overhead per block, or 3.125% if the > block's data is 512

Re: [zfs-discuss] Dedicated metadata devices

2012-08-25 Thread Sašo Kiselkov
On 08/25/2012 11:53 AM, Jim Klimov wrote: >> No they're not, here's l2arc_buf_hdr_t a per-buffer structure >> held for >> buffers which were moved to l2arc: >> >> typedef struct l2arc_buf_hdr { >> l2arc_dev_t *b_dev; >> uint64_t b_daddr; >> } l2arc_buf_hdr_t; >> >> That's about 16-bytes overhead p

Re: [zfs-discuss] Dedicated metadata devices

2012-08-25 Thread Jim Klimov
2012-08-25 15:46, Sašo Kiselkov wrote: The difference is that when you want to go fetch a block from a metaxel, you still need some way to reference it. Either you use direct references (i.e. ARC entries as above), or you use an indirect mechanism, which means that for each read you will need to

Re: [zfs-discuss] slow speed problem with a new SAS shelf

2012-08-25 Thread Yuri Vorobyev
25.07.2012 9:29, Yuri Vorobyev пишет: I faced with a strange performance problem with new disk shelf. We a using ZFS system with SATA disks for a while. What OS and release? Oh. I forgot this important thing. It is OpenIndiana oi_151a5 now. New testing data: I reboot to first boot enviro