Here are the xbench results from my 1.5TB Seagate disks, HFS+ vs ZFS.. Now the numbers are to be taken with a grain of salt since ZFS does a bunch of magic to make these look much more impressive then they actually are... However I want everyone to note the massive improvments in RANDOM IO, this is going to be a godsend for Solid State Disks.
HFS+ RESULTS ------------- Results 86.87 System Info Xbench Version 1.3 System Version 10.5.6 (9G55) Physical RAM 4096 MB Model G31M-ES2L Drive Type ST31500341AS ST31500341AS Disk Test 86.87 Sequential 211.89 Uncached Write 218.75 134.31 MB/sec [4K blocks] Uncached Write 202.31 114.47 MB/sec [256K blocks] Uncached Read 185.25 54.21 MB/sec [4K blocks] Uncached Read 252.17 126.74 MB/sec [256K blocks] Random 54.64 Uncached Write 17.84 1.89 MB/sec [4K blocks] Uncached Write 337.64 108.09 MB/sec [256K blocks] Uncached Read 112.10 0.79 MB/sec [4K blocks] Uncached Read 190.03 35.26 MB/sec [256K blocks] ZFS RESULTS -------------- Results 289.91 System Info Xbench Version 1.3 System Version 10.5.6 (9G55) Physical RAM 4096 MB Model G31M-ES2L Disk Test 289.91 Sequential 414.43 Uncached Write 333.94 205.04 MB/sec [4K blocks] Uncached Write 4492.29 2541.74 MB/sec [256K blocks] Uncached Read 1479.63 433.02 MB/sec [4K blocks] Uncached Read 173.64 87.27 MB/sec [256K blocks] Random 222.93 Uncached Write 65.96 6.98 MB/sec [4K blocks] Uncached Write 7946.32 2543.91 MB/sec [256K blocks] Uncached Read 607.38 4.30 MB/sec [4K blocks] Uncached Read 989.75 183.66 MB/sec [256K blocks]
Now I havent formatted any of my SSD's as ZFS yet, I am using it for my boot drive currently so it remains HFS+.. (My other one is in my webserver and kicking butt with almost limitless read IO) Here are the results from it, note that it appears to be slower than the Seagtate disk but in real world testing I have found it to be much faster than the Seagate.. For examle when verifying a disk image off the SSD provides a constant 130MB/s read while the seagate fluxuates between 70MB/s and 230MB/s but on average it sticks arround 85MB/s and the verification process takes longer.. Booting off the SSD and suspending VM's to the SSD are magnitudes faster than the mechanical drive..
The important thing here is to see how bad the SSD chokes on Random Writes, this is a problem with all the SSD's I have played with. ZFS removes the randomness by queueing up random writes into sequential data blocks... I really hope Snow Leopard lets me format and boot off a ZFS file system. (can anyone confirm this?)
SSD HFS+ -------------- Results 81.84 System Info Xbench Version 1.3 System Version 10.5.6 (9G55) Physical RAM 4096 MB Model G31M-ES2L Drive Type OCZ SOLID_SSD OCZ SOLID_SSD Disk Test 81.84 Sequential 112.45 Uncached Write 133.86 82.19 MB/sec [4K blocks] Uncached Write 138.05 78.11 MB/sec [256K blocks] Uncached Read 59.82 17.51 MB/sec [4K blocks] Uncached Read 241.51 121.38 MB/sec [256K blocks] Random 64.33 Uncached Write 19.20 2.03 MB/sec [4K blocks] Uncached Write 120.67 38.63 MB/sec [256K blocks] Uncached Read 2426.65 17.20 MB/sec [4K blocks] Uncached Read 714.65 132.61 MB/sec [256K blocks]
I do have one question I am having troble locationg an answer for, With ZFS drives in a JBOD it appears that each disk has its own file system and ZFS combines the pool to look like a large file system.. Does this mean if there is a drive failure the FS can recover w/out loosing data on other disks? (unlike consolidated disks from osx soft raid) All I can find on google says that ZFS wont automatically recover but its easier to recover the data when this does happen when compared to other JBOD implementations.. cant find any specifics or procedures regarding this though.
And finally, here are my hopes and expectations for Snow Leopards ZFS Implementation:
1. Use of ZFS for main OS disk
2. Ability to use Time Machine to backup to and from a ZFS disk
3. ZFS Pool Managment in Disk Manager
4. Remove external drives from the ZFS pool by Ejecting through GUI (USB Thumb disks are going to love ZFS!)
5. Ability to delete files off the ZFS w/out droping to console to delete files/trash
I dont know if ZFS is in the Snow Leopard Beta, it seems few people are as intrested in it as I am.. If anyone has the beta and can answer some of my questions I'd appriceate it..
-R



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