Re: [zfs-discuss] zfs read-ahead and L2ARC

2012-01-11 Thread Jim Klimov
2012-01-11 1:26, Jim Klimov пишет: To follow on the subject of VDEV caching, even if only of metadata, in oi_148a, I have found the disabling entry in /etc/system of the LiveUSB: set zfs:zfs_vdev_cache_size=0 Now that I have the cache turned on and my scrub continues, cache efficiency so far

Re: [zfs-discuss] Unable to allocate dma memory for extra SGL

2012-01-11 Thread Hung-Sheng Tsao (Lao Tsao 老曹) Ph. D.
On 1/10/2012 9:44 PM, Ray Van Dolson wrote: On Tue, Jan 10, 2012 at 06:23:50PM -0800, Hung-Sheng Tsao (laoTsao) wrote: how is the ram size what is the zpool setup and what is your hba and hdd size and type Hmm, actually this system has only 6GB of memory. For some reason I though it had

[zfs-discuss] RFE: add an option/attribute to import ZFS pool without automounting/sharing ZFS datasets

2012-01-11 Thread Jim Klimov
I think about adding the following RFE to illumos bugtracker: add an option/attribute to import ZFS pool without automounting/sharing ZFS datasets I wonder if something like this (like a tricky workaround) is already in place? -- My rationale is the currently ongoing repairs and inspections

Re: [zfs-discuss] RFE: add an option/attribute to import ZFS pool without automounting/sharing ZFS datasets

2012-01-11 Thread Darren J Moffat
On 01/11/12 11:48, Jim Klimov wrote: I think about adding the following RFE to illumos bugtracker: add an option/attribute to import ZFS pool without automounting/sharing ZFS datasets I wonder if something like this (like a tricky workaround) is already in place? -N

Re: [zfs-discuss] RFE: add an option/attribute to import ZFS pool without automounting/sharing ZFS datasets

2012-01-11 Thread Jim Klimov
2012-01-11 16:00, Darren J Moffat пишет: On 01/11/12 11:48, Jim Klimov wrote: I think about adding the following RFE to illumos bugtracker: add an option/attribute to import ZFS pool without automounting/sharing ZFS datasets I wonder if something like this (like a tricky workaround) is

[zfs-discuss] How many rollback TXGs in a ring for 4k drives?

2012-01-11 Thread Jim Klimov
Hello all, I found this dialog on the zfs-de...@zfsonlinux.org list, and I'd like someone to confirm-or-reject the discussed statement. Paraphrasing in my words and understanding: Labels, including Uberblock rings, are fixed 256KB in size each, of which 128KB is the UB ring. Normally there

[zfs-discuss] Idea: ZFS and on-disk ECC for blocks

2012-01-11 Thread Jim Klimov
Hello all, I have a new crazy idea of the day ;) Some years ago there was an idea proposed in one of ZFS developers' blogs (maybe Jeff's? sorry, can't find and link it now) that went somewhat along these lines: Modern disks have some ECC/CRC codes for each sector, and uses them to test

Re: [zfs-discuss] Idea: ZFS and on-disk ECC for blocks

2012-01-11 Thread Nico Williams
On Wed, Jan 11, 2012 at 9:16 AM, Jim Klimov jimkli...@cos.ru wrote: I've recently had a sort of an opposite thought: yes, ZFS redundancy is good - but also expensive in terms of raw disk space. This is especially bad for hardware space-constrained systems like laptops and home-NASes, where

Re: [zfs-discuss] Idea: ZFS and on-disk ECC for blocks

2012-01-11 Thread Jim Klimov
2012-01-11 20:40, Nico Williams пишет: On Wed, Jan 11, 2012 at 9:16 AM, Jim Klimovjimkli...@cos.ru wrote: I've recently had a sort of an opposite thought: yes, ZFS redundancy is good - but also expensive in terms of raw disk space. This is especially bad for hardware space-constrained systems

[zfs-discuss] Clarifications wanted for ZFS spec

2012-01-11 Thread Jim Klimov
I'm reading the ZFS On-disk Format PDF (dated 2006 - are there newer releases?), and have some questions regarding whether it is outdated: 1) On page 16 it has the following phrase (which I think is in general invalid): The value stored in offset is the offset in terms of sectors (512 byte

Re: [zfs-discuss] How many rollback TXGs in a ring for 4k drives?

2012-01-11 Thread Richard Elling
On Jan 11, 2012, at 5:01 AM, Jim Klimov wrote: Hello all, I found this dialog on the zfs-de...@zfsonlinux.org list, and I'd like someone to confirm-or-reject the discussed statement. Paraphrasing in my words and understanding: Labels, including Uberblock rings, are fixed 256KB in size each,

Re: [zfs-discuss] ZFS and spread-spares (kinda like GPFS declustered RAID)?

2012-01-11 Thread Daniel Carosone
On Sun, Jan 08, 2012 at 06:25:05PM -0800, Richard Elling wrote: ZIL makes zero impact on resilver. I'll have to check to see if L2ARC is still used, but due to the nature of the ARC design, read-once workloads like backup or resilver do not tend to negatively impact frequently used data.

Re: [zfs-discuss] ZFS and spread-spares (kinda like GPFS declustered RAID)?

2012-01-11 Thread Daniel Carosone
On Thu, Jan 12, 2012 at 03:05:32PM +1100, Daniel Carosone wrote: On Sun, Jan 08, 2012 at 06:25:05PM -0800, Richard Elling wrote: ZIL makes zero impact on resilver. I'll have to check to see if L2ARC is still used, but due to the nature of the ARC design, read-once workloads like backup or