[zfs-discuss] new labelfix needed
Hi, labelfix http://www.opensolaris.org/jive/thread.jspa?messageID=229969 saved already a lot of data as it makes dettached devices importable. A quick test today shows labelfix won't work anymore: #uname -a SunOs bigmama 5.11 snv_127 i86pc 386 i86pc Solaris #./labelfix /dev/rdsk/c0d1s4 ld.so.1: labelfix: fatal: relocation error: file labelfix: symbol zio_checksum: referenced symbol not found Killed # Could anyone with the right skills have a look at it? As this feature didn't make it into zfs it would be nice to have it again. bbr -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] new labelfix needed
On Mon, 30 Aug 2010, Benjamin Brumaire wrote: As this feature didn't make it into zfs it would be nice to have it again. Better to spend time fixing the problem that requires a 'labelfix' as a workaround, surely. What's causing the need to fix vdev labels? ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] 4k block alignment question (X-25E)
On Mon, Aug 30, 2010 at 10:11:32PM -0700, Christopher George wrote: I was wondering if anyone had a benchmarking showing this alignment mattered on the latest SSDs. My guess is no, but I have no data. I don't believe there can be any doubt whether a Flash based SSD (tier1 or not) is negatively affected by partition misalignment. It is intrinsic to the required asymmetric erase/program dual operation and the resultant RMW penalty to perform a write if unaligned. This is detailed in the following vendor benchmarking guidelines (SF-1500 controller): http://www.smartm.com/files/salesLiterature/storage/AN001_Benchmark_XceedIOPSSATA_Apr2010_.pdf Highlight from link - Proper partition alignment is one of the most critical attributes that can greatly boost the I/O performance of an SSD due to reduced read modify‐write operations. It should be noted, the above highlight only applies to Flash based SSD as an NVRAM based SSD does *not* suffer the same fate, as its performance is not bound by or vary with partition (mis)alignment. Here's an article with some benchmarks: http://wikis.sun.com/pages/viewpage.action?pageId=186241353 Seems to really impact IOPS. Ray ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Intermittent ZFS hang
Charles, Just like UNIX, there are several ways to drill down on the problem. I would probably start with a live crash dump (savecore -L) when you see the problem. Another method would be to grap multiple stats commands during the problem to see where you can drill down later. I would probably use this method if the problem lasts for a while and drill down with dtrace base on what I saw. But each method is going to depend on your skill, when looking at the problem. Dave On 08/30/10 16:15, Charles J. Knipe wrote: David, Thanks for your reply. Answers to your questions are below. Is it just ZFS hanging (or what it appears to be is slowing down or blocking) or does the whole system hang?nbsp; br Only the ZFS storage is affected. Any attempt to write to it blocks until the issue passes. Other than that the system behaves normally. I have not, as far as I remember, tried writing to the root pool while this is going on, I'll have to check that next time. I suspect the problem is likely limited to a single pool. What does iostat show during the time period of the slowdown?br What does mpstat show during the time of the slowdown?br br You can look at the metadata statistics by running the following. echo ::arc | mdb -kbr When looking at a ZFS problem, I usually like to gather echo ::spa | mdb -kbr echo ::zio_state | mdb -kbr I will plan to dump information from all of these sources next time I can catch it in the act. Any other diag commands you think might be useful? I suspect you could drill down more with dtrace or lockstat to see where the slowdown is happening. I'm brand new to DTrace. I'm doing some reading now toward being in a position to ask intelligent questions. -Charles -- ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] 4k block alignment question (X-25E)
On Mon, 30 Aug 2010, Christopher George wrote: It should be noted, the above highlight only applies to Flash based SSD as an NVRAM based SSD does *not* suffer the same fate, as its performance is not bound by or vary with partition (mis)alignment. What is a NVRAM based SSD? It seems to me that you are misusing the term NVRAM. Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer,http://www.GraphicsMagick.org/ ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] 4k block alignment question (X-25E)
What is a NVRAM based SSD? It is simply an SSD (Solid State Drive) which does not use Flash, but does use power protected (non-volatile) DRAM, as the primary storage media. http://en.wikipedia.org/wiki/Solid-state_drive I consider the DDRdrive X1 to be a NVRAM based SSD even though we delineate the storage media used depending on host power condition. The X1 exclusively uses DRAM for all IO processing (host is on) and then Flash for permanent non-volatility (host is off). Thanks, Christopher George Founder/CTO www.ddrdrive.com -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] 4k block alignment question (X-25E)
On Mon, Aug 30, 2010 at 3:05 PM, Ray Van Dolson rvandol...@esri.com wrote: I want to fix (as much as is possible) a misalignment issue with an X-25E that I am using for both OS and as an slog device. It's pretty easy to get the alignment right fdisk uses a default of 63/255/*, which isn't easy to change. This makes each cylinder ( 63 * 255 * 512b ). You want ( $cylinder_offset ) * ( 63 * 255 * 512b ) / ( $block_alignment_size ) to be evenly divisible. For a 4k alignment you want the offset to be 8. With fdisk, create your SOLARIS2 partition that uses the entire disk. The partition will be from cylinder 1 to whatever. Cylinder 0 is used for the MBR, so it's automatically un-aligned. When you create slices in format, the MBR cylinder isn't visible, so you have to subtract 1 from the offset, so your first slice should start on cylinder 7. Each additional cylinder should start on a multiple of 8, minus 1. eg: 63, 1999, etc. It doesn't matter if the end of a slice is unaligned, other than to make aligning the next slice easier. -B -- Brandon High : bh...@freaks.com ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Terrible ZFS performance on a Dell 1850 w/ PERC 4e/Si (Sol10U6)
I ran into this issue on my Dell 1850s also. You'll need to go into BIOS, change the PERC controller mode from RAID to SCSI and reboot. Then when the system comes back up it will give a warning about switching RAID controller modes and data loss (Have Backups)!. Then if you boot from DVD/Jumpstart you should see 2 disks and just do a ZFS 2 disk mirror for rpool. Hope this helps... - Robert Loper -- Forwarded message -- From: Andrei Ghimus ghi...@gmail.com To: zfs-discuss@opensolaris.org Date: Mon, 30 Aug 2010 11:05:27 PDT Subject: Re: [zfs-discuss] Terrible ZFS performance on a Dell 1850 w/ PERC 4e/Si (Sol10U6) I have the same problem you do, ZFS performance under Solaris 10 u8 is horrible. When you say passthrough mode, do you mean non-RAID configuration? And if so, could you tell me how you configured it? The best I can manage is to configure each physical drive as a RAID 0 array then export that as a logical drive. All tips/suggestions are appreciated. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] 4k block alignment question (X-25E)
Christopher George wrote: What is a NVRAM based SSD? It is simply an SSD (Solid State Drive) which does not use Flash, but does use power protected (non-volatile) DRAM, as the primary storage media. http://en.wikipedia.org/wiki/Solid-state_drive I consider the DDRdrive X1 to be a NVRAM based SSD even though we delineate the storage media used depending on host power condition. The X1 exclusively uses DRAM for all IO processing (host is on) and then Flash for permanent non-volatility (host is off). NVRAM = non-volatile random access memory. It is a general category. EEPROM = electrically-erasable programmable read-only memory. It is a specific type of NVRAM. Flash memory = memory used in flash devices, commonly NOR or NAND based. It is a specific type of EEPROM, which in turn is a specific type of NVRAM. http://en.wikipedia.org/wiki/Non-volatile_random_access_memory http://en.wikipedia.org/wiki/EEPROM http://en.wikipedia.org/wiki/Flash_memory He means a DRAM based SSD with NVRAM (flash) backup vs. SSDs that use NVRAM (flash) directly. This class of SSD may use DDR DIMMs or may be integrated. Almost all of these devices that retain their data upon power loss are technically NVRAM based. (Exception could be a hard drive based device that uses a DRAM cache equal to its hard drive storage capacity.) It is effectively what you would get if you had a regular flash based SSD with an internal RAM cache equal in size to the nonvolatile storage plus enough energy storage to write out the whole cache upon power loss. I doubt there would be any additional performance beyond what you could see from a RAMDISK carved from main memory (actually there would probably be theoretical lower performance because of lower bus bandwidths). It does effectively solve the problems posed by motherboard physical RAM limits and of an unexpected power loss due to failed power supplies or failed UPSes. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
