Re: [zfs-discuss] Interesting question about L2ARC

2012-09-26 Thread Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- boun...@opensolaris.org] On Behalf Of Jim Klimov Got me wondering: how many reads of a block from spinning rust suffice for it to ultimately get into L2ARC? Just one so it gets into a recent-read list of the ARC and then expires

Re: [zfs-discuss] Interesting question about L2ARC

2012-09-26 Thread Sašo Kiselkov
On 09/26/2012 01:14 PM, Edward Ned Harvey (opensolarisisdeadlongliveopensolaris) wrote: From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- boun...@opensolaris.org] On Behalf Of Jim Klimov Got me wondering: how many reads of a block from spinning rust suffice for it to ultimately

[zfs-discuss] Different size / manufacturer L2ARC

2012-09-26 Thread Matt Van Mater
I've looked on the mailing list (the evil tuning wikis are down) and haven't seen a reference to this seemingly simple question... I have two OCZ Vertex 4 SSDs acting as L2ARC. I have a spare Crucial SSD (about 1.5 years old) that isn't getting much use and i'm curious about adding it to the

Re: [zfs-discuss] Different size / manufacturer L2ARC

2012-09-26 Thread Sašo Kiselkov
On 09/26/2012 05:08 PM, Matt Van Mater wrote: I've looked on the mailing list (the evil tuning wikis are down) and haven't seen a reference to this seemingly simple question... I have two OCZ Vertex 4 SSDs acting as L2ARC. I have a spare Crucial SSD (about 1.5 years old) that isn't getting

Re: [zfs-discuss] Different size / manufacturer L2ARC

2012-09-26 Thread Matt Van Mater
If the added device is slower, you will experience a slight drop in per-op performance, however, if your working set needs another SSD, overall it might improve your throughput (as the cache hit ratio will increase). Thanks for your fast reply! I think I know the answer to this question,

Re: [zfs-discuss] Different size / manufacturer L2ARC

2012-09-26 Thread Sašo Kiselkov
On 09/26/2012 05:18 PM, Matt Van Mater wrote: If the added device is slower, you will experience a slight drop in per-op performance, however, if your working set needs another SSD, overall it might improve your throughput (as the cache hit ratio will increase). Thanks for your fast

Re: [zfs-discuss] Different size / manufacturer L2ARC

2012-09-26 Thread Dan Swartzendruber
On 9/26/2012 11:18 AM, Matt Van Mater wrote: If the added device is slower, you will experience a slight drop in per-op performance, however, if your working set needs another SSD, overall it might improve your throughput (as the cache hit ratio will increase). Thanks for your

Re: [zfs-discuss] Different size / manufacturer L2ARC

2012-09-26 Thread Matt Van Mater
Excellent thanks to you both. I knew of both those methods and wanted to make sure i wasn't missing something! On Wed, Sep 26, 2012 at 11:21 AM, Dan Swartzendruber dswa...@druber.comwrote: ** On 9/26/2012 11:18 AM, Matt Van Mater wrote: If the added device is slower, you will experience a

[zfs-discuss] zvol refreservation size

2012-09-26 Thread Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
When I create a 50G zvol, it gets volsize 50G, and it gets used and refreservation 51.6G I have some filesystems already in use, hosting VM's, and I'd like to mimic the refreservation setting on the filesystem, as if I were smart enough from the beginning to have used the zvol. So my question

[zfs-discuss] vm server storage mirror

2012-09-26 Thread Edward Ned Harvey (opensolarisisdeadlongliveopensolaris)
Here's another one. Two identical servers are sitting side by side. They could be connected to each other via anything (presently using crossover ethernet cable.) And obviously they both connect to the regular LAN. You want to serve VM's from at least one of them, and even if the VM's

Re: [zfs-discuss] vm server storage mirror

2012-09-26 Thread Freddie Cash
If you're willing to try FreeBSD, there's HAST (aka high availability storage) for this very purpose. You use hast to create mirror pairs using 1 disk from each box, thus creating /dev/hast/* nodes. Then you use those to create the zpool one the 'primary' box. All writes to the pool on the

Re: [zfs-discuss] vm server storage mirror

2012-09-26 Thread matthew patton
head units crash or do weird things, but disks persist. There are a couple of HA head-unit solutions out there but most of them have their own separate storage and they effectively just send transaction groups to each other. The other way is to connect 2 nodes to an external SAS/FC chassis.

Re: [zfs-discuss] zvol refreservation size

2012-09-26 Thread Matthew Ahrens
On Wed, Sep 26, 2012 at 10:28 AM, Edward Ned Harvey (opensolarisisdeadlongliveopensolaris) opensolarisisdeadlongliveopensola...@nedharvey.com wrote: When I create a 50G zvol, it gets volsize 50G, and it gets used and refreservation 51.6G ** ** I have some filesystems already in use,

Re: [zfs-discuss] vm server storage mirror

2012-09-26 Thread Tim Cook
On Wed, Sep 26, 2012 at 12:54 PM, Edward Ned Harvey (opensolarisisdeadlongliveopensolaris) opensolarisisdeadlongliveopensola...@nedharvey.com wrote: Here's another one. ** ** Two identical servers are sitting side by side. They could be connected to each other via anything (presently

Re: [zfs-discuss] vm server storage mirror

2012-09-26 Thread Richard Elling
On Sep 26, 2012, at 10:54 AM, Edward Ned Harvey (opensolarisisdeadlongliveopensolaris) opensolarisisdeadlongliveopensola...@nedharvey.com wrote: Here's another one. Two identical servers are sitting side by side. They could be connected to each other via anything (presently using

Re: [zfs-discuss] Interesting question about L2ARC

2012-09-26 Thread Richard Elling
On Sep 26, 2012, at 4:28 AM, Sašo Kiselkov skiselkov...@gmail.com wrote: On 09/26/2012 01:14 PM, Edward Ned Harvey (opensolarisisdeadlongliveopensolaris) wrote: From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- boun...@opensolaris.org] On Behalf Of Jim Klimov Got me