Return-Path: Delivered-To: apmail-hadoop-common-user-archive@www.apache.org Received: (qmail 30390 invoked from network); 2 Dec 2010 15:25:43 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 2 Dec 2010 15:25:43 -0000 Received: (qmail 51976 invoked by uid 500); 2 Dec 2010 15:25:40 -0000 Delivered-To: apmail-hadoop-common-user-archive@hadoop.apache.org Received: (qmail 51781 invoked by uid 500); 2 Dec 2010 15:25:40 -0000 Mailing-List: contact common-user-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: common-user@hadoop.apache.org Delivered-To: mailing list common-user@hadoop.apache.org Received: (qmail 51771 invoked by uid 99); 2 Dec 2010 15:25:39 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 02 Dec 2010 15:25:39 +0000 X-ASF-Spam-Status: No, hits=0.0 required=10.0 tests= X-Spam-Check-By: apache.org Received-SPF: neutral (athena.apache.org: local policy) Received: from [64.81.36.244] (HELO foobar.kobold.org) (64.81.36.244) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 02 Dec 2010 15:25:39 +0000 Received: from owl.kobold.org (owl.kobold.org [192.168.1.7]) (authenticated bits=0) by foobar.kobold.org (8.14.1/8.14.1) with ESMTP id oB2F6sAB020393 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 2 Dec 2010 07:06:58 -0800 Message-ID: <4CF7BA4E.7050707@hep.caltech.edu> Date: Thu, 02 Dec 2010 07:25:02 -0800 From: Michael Thomas User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.12) Gecko/20101027 Fedora/3.1.6-1.fc13 Thunderbird/3.1.6 MIME-Version: 1.0 To: common-user@hadoop.apache.org Subject: Re: Mounting HDFS as local file system References: <4CF78006.9060407@apache.org> <35DDD480-AA70-4FE6-9C98-D4CE1A9F0F77@cse.unl.edu> In-Reply-To: <35DDD480-AA70-4FE6-9C98-D4CE1A9F0F77@cse.unl.edu> X-Enigmail-Version: 1.1.2 Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary="------------ms000208020706000506080105" --------------ms000208020706000506080105 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 12/02/2010 05:10 AM, Brian Bockelman wrote: >=20 > On Dec 2, 2010, at 5:16 AM, Steve Loughran wrote: >=20 >> On 02/12/10 03:01, Mark Kerzner wrote: >>> Hi, guys, >>> >>> I see that there is MountableHDFS, >>> and I know that it works, but my questions are as follows: >>> >>> - How reliable is it for large storage?; >> >> Shouldn't be any worse than normal HDFS operations. >> >>> - Is it not hiding the regular design questions - we are dealing w= ith >>> NameServers after all, but are trying to use it as a regular file = system? >>> - For example, HDFS is not optimized for many small files that get= >>> written and deleted, but a mounted system will lure one in this di= rection. >> >> Like you say, it's not a conventional posix fs, it hates small files, = where other things may be better. >=20 > I would comment that it's extremely reliable. There's at least one slo= w memory leak in fuse-dfs that I haven't been able to squash, and I typic= ally remount things after a month or two of *heavy* usage. Using the automounter with fuse-dfs has helped us a lot. After 5 minutes of no activity, the fuse-dfs process goes away and the memory leak is cleaned up automatically. We only see the problem when there is constant HDFS usage for days at a time, which unfortunately, has been the rule rather than the exception lately. --Mike > Across all the nodes in our cluster, we probably do a few billion HDFS = operations per day over FUSE. --------------ms000208020706000506080105 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIMVjCC A/gwggLgoAMCAQICASkwDQYJKoZIhvcNAQEFBQAwdTETMBEGCgmSJomT8ixkARkWA25ldDES MBAGCgmSJomT8ixkARkWAkVTMQ4wDAYDVQQKEwVFU25ldDEgMB4GA1UECxMXQ2VydGlmaWNh dGUgQXV0aG9yaXRpZXMxGDAWBgNVBAMTD0VTbmV0IFJvb3QgQ0EgMTAeFw0wMjEyMDUwODAw MDBaFw0xMzAxMjUwODAwMDBaMGkxEzARBgoJkiaJk/IsZAEZFgNvcmcxGDAWBgoJkiaJk/Is ZAEZFghET0VHcmlkczEgMB4GA1UECxMXQ2VydGlmaWNhdGUgQXV0aG9yaXRpZXMxFjAUBgNV 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